A355452 a(n) = 1 if Bernoulli number B_{n} has denominator 6, otherwise 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, 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

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions

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.

Cf. A027642, A067513, A355451.

Sequence in context: A033683 A216284 A360109 * A130638 A030217 A030215

Adjacent sequences: A355449 A355450 A355451 * A355453 A355454 A355455

Keyword

nonn

Author

Antti Karttunen, Jul 12 2022

Status

approved