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A355452
a(n) = 1 if Bernoulli number B_{n} has denominator 6, otherwise 0.
3
0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0
OFFSET
1
FORMULA
a(n) = 1 if A027642(n) = 6, otherwise 0.
a(n) = 1 if A067513(n) = 2, otherwise 0.
For n > 2, a(n) <= A355451(n).
MATHEMATICA
Table[If[Denominator[BernoulliB[n]]==6, 1, 0], {n, 130}] (* Harvey P. Dale, Apr 22 2023 *)
PROG
(PARI) A355452(n) = (6==denominator(bernfrac(n)));
(PARI) A355452(n) = if(n%2, 0, fordiv(n/2, d, if(isprime(2*d+1)&&d>1, return(0))); (1)); \\ After function "is" in A051222
CROSSREFS
Characteristic function of A051222.
Sequence in context: A033683 A216284 A360109 * A130638 A030217 A030215
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 12 2022
STATUS
approved