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A043296 Sum of digits of denominator of Bernoulli number B(2n). 2
6, 3, 6, 3, 12, 12, 6, 6, 24, 6, 12, 12, 6, 15, 12, 6, 6, 30, 6, 12, 15, 15, 12, 15, 12, 15, 24, 15, 12, 42, 6, 6, 21, 3, 24, 21, 6, 3, 15, 6, 21, 15, 6, 12, 21, 6, 6, 24, 6, 12, 15, 15, 12, 30, 15, 24, 6, 15, 6, 39, 6, 3, 42, 6, 24, 24, 6, 6, 30, 33, 6, 42, 6, 15, 21, 3, 12, 42, 6, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..80.

FORMULA

a(n) = A007953(A002445(n)). - Michel Marcus, Feb 16 2021

EXAMPLE

Denominator(B(2*9))=798 and 7+9+8=24 hence a(9)=24.

MATHEMATICA

Total[IntegerDigits[#]]&/@Denominator[BernoulliB[2*Range[80]]] (* Harvey P. Dale, Jul 02 2017 *)

PROG

(PARI) a(n) = sumdigits(denominator(bernfrac(2*n))); \\ Michel Marcus, Feb 16 2021

(Python)

from sympy import bernoulli

def a(n): return sum(map(int, str(bernoulli(2*n).denominator())))

print([a(n) for n in range(1, 81)]) # Michael S. Branicky, Jun 03 2021

CROSSREFS

Cf. A002445, A007953, A043295.

Sequence in context: A194625 A165065 A069938 * A199186 A176715 A229522

Adjacent sequences:  A043293 A043294 A043295 * A043297 A043298 A043299

KEYWORD

base,easy,nonn

AUTHOR

Benoit Cloitre, Mar 24 2002

STATUS

approved

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Last modified December 3 21:17 EST 2021. Contains 349468 sequences. (Running on oeis4.)