login
Search: a061274 -id:a061274
     Sort: relevance | references | number | modified | created      Format: long | short | data
Number of primes between successive powers of e (= 2.718281828...).
+10
3
1, 3, 4, 8, 18, 45, 104, 246, 590, 1447, 3582, 8864, 22216, 55989, 141738, 360486, 920892, 2360953, 6073160, 15664216, 40510215, 105017120, 272821646, 710143301, 1851830021, 4836984396, 12653549540, 33148606878, 86954036990, 228373959896, 600482317125, 1580587864193, 4164596465439, 10983396620288
OFFSET
0,2
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 0..38
FORMULA
a(n) ~ 1/n * e^n * (e-1).
EXAMPLE
a(0) = 1 as 2 is the only between 1 and e. a(4) = 18, as there are 18 primes between e^4 = 54.59815... and e^5 = 148.4131591...
MAPLE
# To find all primes between ceiling(base^(n-1)) and floor(base^n). This uses the Maple function 'isprime', which is a probabilistic primality testing routine.
base := exp(1); maxx := 15; for n from 1 to maxx do for i from ceil(base^(n-1)) to floor(base^(n)) do if (isprime(i)) then numPrimes := numPrimes + 1: end if; od; printf("Number of primes between ceil(%f)^%d and floor(%f)^%d is %d ", base, n-1, base, n, numPrimes); od; # Winston C. Yang (winston(AT)cs.wisc.edu), May 17 2001
MATHEMATICA
Differences[PrimePi[#]&/@(E^Range[0, 35])] (* Harvey P. Dale, May 03 2023 *)
CROSSREFS
Cf. A061274.
First differences of A040014.
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 25 2001
EXTENSIONS
More terms from Winston C. Yang (winston(AT)cs.wisc.edu), May 17 2001
a(29)-a(33) from Robert G. Wilson v, Jun 05 2016
STATUS
approved
Number of primes less than or equal to Pi^n.
+10
3
0, 2, 4, 11, 25, 62, 162, 433, 1175, 3229, 9042, 25549, 73050, 210356, 610041, 1779830, 5218745, 15372304, 45455747, 134882577, 401480918, 1198344171, 3585783711, 10754085805, 32319203663, 97312548674, 293515297707, 886720888966, 2682778745396, 8127887397064
OFFSET
0,2
LINKS
David Baugh, Table of n, a(n) for n = 0..52 (terms n = 27..52 found using Kim Walisch's primecount program)
FORMULA
a(n) = A000720(A001672(n)). - Michel Marcus, Oct 05 2020
MATHEMATICA
Do[ Print[ PrimePi[Pi^n]], {n, 0, 28}]
PROG
(PARI) a(n) = primepi(Pi^n); \\ Michel Marcus, Oct 05 2020
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Robert G. Wilson v, Jun 18 2002
EXTENSIONS
a(27)-a(29) from David Baugh, Oct 05 2020
STATUS
approved
Number of primes between Pi^(prime(n)) and Pi^(prime(n+1)).
+10
0
7, 51, 371, 25116, 184807, 15161948, 119510273, 10619203228, 8117133311259, 66755371425339, 59943578764218680, 5202903726035784628, 44211655386352360485, 4351545315671679793432
OFFSET
1,1
FORMULA
a(n) = A071973(prime(n+1)) - A071973(prime(n)). - Amiram Eldar, Jun 14 2024
EXAMPLE
7 primes between Pi^2 (9.8...) and Pi^3 (31.0...).
51 primes between Pi^3 (31.0...) and Pi^5 (306.0...).
371 primes between Pi^5 (306.0...) and Pi^7 (3020.29...).
MATHEMATICA
Table[PrimePi[Pi^(Prime[n + 1])] - PrimePi[Pi^(Prime[n])], {n, 1, 8}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
a(9)-a(14) calculated from the data at A071973 and added by Amiram Eldar, Jun 14 2024
STATUS
approved

Search completed in 0.004 seconds