The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A306509 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A306509

a(n) is the number of divisors of the sum of digits of n.
(history; published version)

#17 by Harvey P. Dale at Tue Aug 03 12:33:48 EDT 2021

STATUS

editing

approved

#16 by Harvey P. Dale at Tue Aug 03 12:33:46 EDT 2021

MATHEMATICA

Table[DivisorSigma[0, Total[IntegerDigits[n]]], {n, 120}] (* Harvey P. Dale, Aug 03 2021 *)

STATUS

approved

editing

#15 by N. J. A. Sloane at Mon Feb 25 20:45:53 EST 2019

STATUS

proposed

approved

#14 by Rémy Sigrist at Mon Feb 25 14:09:10 EST 2019

STATUS

editing

proposed

#13 by Rémy Sigrist at Mon Feb 25 14:08:58 EST 2019

FORMULA

a(10*n) = a(n). - Rémy Sigrist, Feb 25 2019

STATUS

proposed

editing

Discussion

Mon Feb 25

14:09

Rémy Sigrist: added formula

#12 by Ctibor O. Zizka at Thu Feb 21 12:43:48 EST 2019

STATUS

editing

proposed

Discussion

Fri Feb 22

01:36

Michel Marcus: yes for me

#11 by Ctibor O. Zizka at Thu Feb 21 12:42:48 EST 2019

NAME

a(n) = A000005(A007953(is the number of divisors of the sum of digits of n)).

COMMENTS

a(n) is the number of divisors of the sum of digits of n.

Discussion

Thu Feb 21

12:43

Ctibor O. Zizka: yes, switched. Ok ?

#10 by Ctibor O. Zizka at Thu Feb 21 12:41:10 EST 2019

FORMULA

a(n) = A000005(A007953(n)).

STATUS

proposed

editing

#9 by Michel Marcus at Thu Feb 21 01:19:45 EST 2019

STATUS

editing

proposed

#8 by Michel Marcus at Thu Feb 21 01:19:16 EST 2019

COMMENTS

a(n) is the number of divisors of the sum of digits of n.

STATUS

proposed

editing

Discussion

Thu Feb 21

01:19

Michel Marcus: I added a comment. It could be the name, and current name would be a formula  ?