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A043296
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Sum of digits of denominator of Bernoulli number B(2n).
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2
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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
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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Denominator(B(2*9))=798 and 7+9+8=24 hence a(9)=24.
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MATHEMATICA
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Total[IntegerDigits[#]]&/@Denominator[BernoulliB[2*Range[80]]] (* Harvey P. Dale, Jul 02 2017 *)
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PROG
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(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())))
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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STATUS
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approved
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