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Revision History for A212645

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Showing entries 1-10 | older changes
a(n) = number of excess prime divisors of A181800(n) (n-th powerful number that is the first integer of its prime signature).
(history; published version)
#11 by Alois P. Heinz at Sun Jul 14 08:22:00 EDT 2019
STATUS

proposed

approved

#10 by Amiram Eldar at Sun Jul 14 08:06:24 EDT 2019
STATUS

editing

proposed

#9 by Amiram Eldar at Sun Jul 14 06:50:13 EDT 2019
LINKS

Amiram Eldar, <a href="/A212645/b212645.txt">Table of n, a(n) for n = 1..10000</a>

STATUS

approved

editing

#8 by T. D. Noe at Wed Jun 27 13:14:15 EDT 2012
STATUS

editing

approved

#7 by T. D. Noe at Wed Jun 27 13:14:10 EDT 2012
DATA

0, 1, 2, 3, 4, 2, 5, 3, 6, 4, 4, 7, 5, 5, 8, 6, 6, 3, 9, 7, 6, 7, 4, 10, 8, 7, 8, 5, 11, 9, 8, 5, 9, 6, 8, 12, 10, 9, 6, 10, 7, 9, 13, 11, 10, 7, 6, 11, 8, 10, 7, 14, 12, 11, 8, 4, 10, 7, 12, 9, 11, 8, 15, 13, 12, 9, 5, 11, 8, 13, 10, 12, 9, 16, 14, 8, 13, 10, 6, 12, 9, 9, 14, 11, 13, 10

STATUS

proposed

editing

#6 by Matthew Vandermast at Sun Jun 24 00:16:28 EDT 2012
STATUS

editing

proposed

#5 by Matthew Vandermast at Sun Jun 24 00:16:08 EDT 2012
COMMENTS

The excess of n, or A046660(n), is a function of the second signature of n (cf. A212172). Since A181800 gives the first integer of each second signature, this sequence gives the value of A046660 for each second signature in order of its first appearance. a Each nonnegative integer n occurs A000041(n) is also times in the number of prime factors of A212638(n) when repetitions are countedsequence.

Each nonnegative integer n occurs A000041a(n) times in is also the sequencenumber of prime factors of A212638(n), counted with multiplicity.

#4 by Matthew Vandermast at Fri Jun 15 23:24:52 EDT 2012
NAME

a(n) = number of excess prime divisors of A181800(n) (n-th powerful number that is the first integer of each its prime signature).

DATA

0, 1, 2, 3, 4, 2, 5, 3, 6, 4, 4, 7, 5, 5, 8, 6, 6, 3, 9, 7, 6, 7, 4, 10, 8, 7, 8, 5, 11, 9, 8, 5, 9, 6, 8, 12, 10, 9, 6, 10, 7, 9, 13, 11, 10, 7, 6, 11, 8, 10, 7, 14, 12, 11, 8, 4, 10, 7, 12, 9, 11, 8, 15, 13, 12, 9, 5, 11, 8, 13, 10, 12, 9, 16, 14, 8, 13, 10, 6, 12, 9, 9, 14, 11, 13, 10, 17, 6, 12

EXAMPLE

36 (2^2*3^2, or 2*2*3*3) has 4 prime factors when repetitions are counted, but only 2 distinct prime factors. Therefore, its "excess " as defined in A046660 is (4-2) = 2. Since 36 = A181800(6), a(6) = 2.

Discussion
Sat Jun 23
03:28
OEIS Server: This sequence has not been edited or commented on for a week
yet is not proposed for review.  If it is ready for review, please
visit https://oeis.org/draft/A212645 and click the button that reads
"These changes are ready for review by an OEIS Editor."

Thanks.
  - The OEIS Server
#3 by Matthew Vandermast at Fri Jun 15 23:19:49 EDT 2012
NAME

A046660 indexed by second signature (cf. A212172): a(n) = number of excess prime divisors of A181800(n) (n-th powerful number that is the first integer of each prime signature).

COMMENTS

The excess of n, or A046660(n) , is a function of the second signature of n (cf. A212172). The sequence Since A181800 gives the smallest first integer of each second signature, this sequence gives the value of A046660 for each second signature in order of its first appearance. a(n) is also the number of prime factors of A212638(n) when repetitions are counted.

Each nonnegative integer n occurs A000041(n) times in the sequence.

CROSSREFS

A rearrangement of A036042; each nonnegative integer n appears A000041(n) times in the sequence.

A rearrangement of A036042.

#2 by Matthew Vandermast at Sat Jun 09 18:34:53 EDT 2012
NAME

allocated for Matthew VandermastA046660 indexed by second signature (cf. A212172): a(n) = excess of A181800(n).

DATA

0, 1, 2, 3, 4, 2, 5, 3, 6, 4, 4, 7, 5, 5, 8, 6, 6, 3, 9, 7, 6, 7, 4, 10, 8, 7, 8, 5, 11, 9, 8, 5, 9, 6, 8, 12, 10, 9, 6, 10, 7, 9, 13, 11, 10, 7, 6, 11, 8, 10, 7, 14, 12, 11, 8, 4, 10, 7, 12, 9, 11, 8, 15, 13, 12, 9, 5, 11, 8, 13, 10, 12, 9, 16, 14, 8, 13, 10, 6, 12, 9, 9, 14, 11, 13, 10, 17, 6, 12

OFFSET

1,3

COMMENTS

A046660(n) is a function of the second signature of n (cf. A212172). The sequence A181800 gives the smallest integer of each second signature.

FORMULA

a(n) = A046660(A181800(n)) = A212639(n)-A212179(n).

a(n) = A001222(A212638(n)).

EXAMPLE

36 (2^2*3^2, or 2*2*3*3) has 4 prime factors when repetitions are counted, but only 2 distinct prime factors. Therefore, its excess as defined in A046660 is (4-2) = 2. Since 36 = A181800(6), a(6) = 2.

CROSSREFS

Cf. A046660, A181800, A212172, A212176, A212179, A212638, A212639, A212647.

A rearrangement of A036042; each nonnegative integer n appears A000041(n) times in the sequence.

KEYWORD

allocated

nonn

AUTHOR

Matthew Vandermast, Jun 09 2012

STATUS

approved

editing

Discussion
Sat Jun 09
18:39
Matthew Vandermast: Please wait until I submit this for review before making a pink box comment. 
I'm much more comfortable not getting comments on the website until I submit,
but I know from experience that the opposite can happen. Thanks!