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Search: a086343 -id:a086343
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Integers not generated by b(n) = b(floor(n/2)) + n (cf. A005187).
+10
84
2, 5, 6, 9, 12, 13, 14, 17, 20, 21, 24, 27, 28, 29, 30, 33, 36, 37, 40, 43, 44, 45, 48, 51, 52, 55, 58, 59, 60, 61, 62, 65, 68, 69, 72, 75, 76, 77, 80, 83, 84, 87, 90, 91, 92, 93, 96, 99, 100, 103, 106, 107, 108, 111, 114, 115, 118, 121, 122, 123, 124, 125, 126, 129
OFFSET
1,1
COMMENTS
Note that the lengths of the consecutive runs in a(n) form sequence A001511.
Integers that are not a sum of distinct integers of the form 2^k-1. - Vladeta Jovovic, Jan 24 2003
Also n! never ends in this many 0's in base 2 - Carl R. White, Jan 21 2008
A079559(a(n)) = 0. - Reinhard Zumkeller, Mar 18 2009
These numbers are dead-end points when trying to apply the iterated process depicted in A071542 in reverse, i.e. these are positive integers i such that there does not exist k with A000120(i+k)=k. See also comments at A179016. - Antti Karttunen, Oct 26 2012
Conjecture: a(n)=b(n) defined as b(1)=2, for n>1, b(n+1)=b(n)+1 if n is already in the sequence, b(n+1)=b(n)+3 otherwise. If so, then see Cloitre comment in A080578. - Ralf Stephan, Dec 27 2013
Numbers n for which A257265(m) = 0. - Reinhard Zumkeller, May 06 2015. Typo corrected by Antti Karttunen, Aug 08 2015
FORMULA
a(n) = A080578(n+1) - 2 = A080468(n+1) + 2*n (conjectured). - Ralf Stephan, Dec 27 2013
From Antti Karttunen, Aug 08 2015: (Start)
Other identities. For all n >= 1:
A234017(a(n)) = n.
A256992(a(n)) = n.
A257126(n) = a(n) - A005187(n).
(End)
EXAMPLE
Since A005187 begins 0 1 3 4 7 8 10 11 15 16 18 19 22 23 25 26 31... this sequence begins 2 5 6 9 12 13 14 17 20 21
MATHEMATICA
a[0] = 0; a[1] = 1; a[n_Integer] := a[Floor[n/2]] + n; b = {}; Do[ b = Append[b, a[n]], {n, 0, 105}]; c =Table[n, {n, 0, 200}]; Complement[c, b]
(* Second program: *)
t = Table[IntegerExponent[(2n)!, 2], {n, 0, 100}]; Complement[Range[t // Last], t] (* Jean-François Alcover, Nov 15 2016 *)
PROG
(Haskell)
a055938 n = a055938_list !! (n-1)
a055938_list = concat $
zipWith (\u v -> [u+1..v-1]) a005187_list $ tail a005187_list
-- Reinhard Zumkeller, Nov 07 2011
(PARI) L=listcreate(); for(n=1, 1000, for(k=2*n-hammingweight(n)+1, 2*n+1-hammingweight(n+1), listput(L, k))); Vec(L) \\ Ralf Stephan, Dec 27 2013
(Scheme) ;; utilizing COMPLEMENT-macro from Antti Karttunen's IntSeq-library)
(define A055938 (COMPLEMENT 1 A005187))
;; Antti Karttunen, Aug 08 2015
(Python)
def a053644(n): return 0 if n==0 else 2**(len(bin(n)[2:]) - 1)
def a043545(n):
x=bin(n)[2:]
return int(max(x)) - int(min(x))
def a079559(n): return 1 if n==0 else a043545(n + 1)*a079559(n + 1 - a053644(n + 1))
print([n for n in range(1, 201) if a079559(n)==0]) # Indranil Ghosh, Jun 11 2017, after the comment by Reinhard Zumkeller
CROSSREFS
Complement of A005187. Setwise difference of A213713 and A213717.
Row 1 of arrays A257264, A256997 and also of A255557 (when prepended with 1). Equally: column 1 of A256995 and A255555.
Cf. also arrays A254105, A254107 and permutations A233276, A233278.
Left inverses: A234017, A256992.
Gives positions of zeros in A213714, A213723, A213724, A213731, A257265, positions of ones in A213725-A213727 and A256989, positions of nonzeros in A254110.
Cf. also A010061 (integers that are not a sum of distinct integers of the form 2^k+1).
Analogous sequence for factorial base number system: A219658, for Fibonacci number system: A219638, for base-3: A096346. Cf. also A136767-A136774.
KEYWORD
easy,nice,nonn
AUTHOR
Alford Arnold, Jul 21 2000
EXTENSIONS
More terms from Robert G. Wilson v, Jul 24 2000
STATUS
approved
Complement of A004128.
+10
13
3, 7, 11, 12, 16, 20, 24, 25, 29, 33, 37, 38, 39, 43, 47, 51, 52, 56, 60, 64, 65, 69, 73, 77, 78, 79, 83, 87, 91, 92, 96, 100, 104, 105, 109, 113, 117, 118, 119, 120, 124, 128, 132, 133, 137, 141, 145, 146, 150, 154, 158, 159, 160, 164, 168, 172, 173, 177, 181, 185
OFFSET
0,1
COMMENTS
Shape sequence for A055938 is A001511; shape sequence for a(n) is A051064; A001511, A051064 and A055457 are p-adic valuations for p = 2, 3 & 5.
Also n! never ends in this many 0's in bases 3 and 6. - Carl R. White, Jan 21 2008
EXAMPLE
A004128 begins 0 1 2 4 5 6 8 9 10 13 14 15 ... therefore a(n) begins 3 7 11 12 16 20 24 25 ...
MAPLE
b:=n->sum(floor(3*n/3^k), k=1..n): {seq(n, n=0..222)} minus {seq(b(n), n=0..150)}; # Emeric Deutsch, Dec 09 2004
MATHEMATICA
A004128 = Log[3, CoefficientList[ Series[ 1/(1+x)^(1/3), {x, 0, 200}], x] // Denominator]; A096346 = Complement[ Range[A004128 // Last], A004128] (* Jean-François Alcover, Feb 19 2015 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Alford Arnold, Aug 04 2004
EXTENSIONS
More terms from Emeric Deutsch, Dec 09 2004
STATUS
approved
a(n) = 4*n - A000120(n).
+10
10
0, 3, 7, 10, 15, 18, 22, 25, 31, 34, 38, 41, 46, 49, 53, 56, 63, 66, 70, 73, 78, 81, 85, 88, 94, 97, 101, 104, 109, 112, 116, 119, 127, 130, 134, 137, 142, 145, 149, 152, 158, 161, 165, 168, 173, 176, 180, 183, 190, 193, 197, 200, 205, 208, 212, 215, 221, 224, 228
OFFSET
0,2
COMMENTS
Partial sums of A090739.
a(n) is also the increasing sequence of exponents of x in Product_{k > 1} (1 + x^(2^k - 1)). - Paul Pearson (ppearson(AT)rochester.edu), Aug 06 2008
Related to partial sums of the Ruler sequence A001511 by a(n) = A005187(2n), therefore {a(n)+1} are the indices of 1's in A252488. - M. F. Hasler, Jan 22 2015
LINKS
Keith Johnson, and Kira Scheibelhut, Rational Polynomials That Take Integer Values at the Fibonacci Numbers, American Mathematical Monthly 123.4 (2016): 338-346. See p. 340.
FORMULA
a(n) = log_2(16^n/A001316(n)). [This was the original definition.]
a(n) = 2n + A005187(n).
a(n) = 3n + A011371(n).
a(n) = 4n - log_2(A001316(n)).
a(n) = log_2(A061549(n)).
2^a(n) = 16^n/A001316(n) = A061549(n).
a(n) = A086343(n) + A001511(n) for n>0. - Alford Arnold, Mar 23 2009
2^a(n) = abs(A067624(n)/A117972(n)). - Johannes W. Meijer, Jul 06 2009
a(n) = Sum_{k>=0} (A030308(n,k)*A000225(k+2)). - Philippe Deléham, Oct 16 2011
a(n) = A005187(2n). - M. F. Hasler, Jan 22 2015
MAPLE
a:=n->simplify(log[2](16^n/(add(modp(binomial(n, k), 2), k=0..n))));
a:=n->simplify(log[2](16^n/(2^(n-(padic[ordp](n!, 2)))))); # Note: n-(padic[ordp](n!, 2)) is the number of 1's in the binary expansion of n. - Paul Pearson (ppearson(AT)rochester.edu), Aug 06 2008
MATHEMATICA
Table[4 n - DigitCount[n, 2, 1], {n, 0, 58}] (* Michael De Vlieger, Nov 06 2016 *)
PROG
(PARI) {a(n) = if( n < 0, 0, 4*n - subst( Pol( binary( n ) ), x, 1) ) } /* Michael Somos, Aug 28 2007 */
(PARI) a(n) = 4*n - hammingweight(n); \\ Michel Marcus, Nov 06 2016
(Sage)
A120738 = lambda n: 4*n - sum(n.digits(2))
print([A120738(n) for n in (0..58)]) # Peter Luschny, Nov 06 2016
(Python 3.10+)
def A120738(n): return (n<<2)-n.bit_count() # Chai Wah Wu, Jul 12 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jun 29 2006
EXTENSIONS
Definition simplified by M. F. Hasler, Dec 29 2012
STATUS
approved

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