A335264 a(n) = Numerator(-4*n^2*Zeta(1 - n)^2*(1 - 2^n)) for n >= 1, a(0) = 0.

0, 1, 1, 0, 1, 0, 1, 0, 17, 0, 775, 0, 477481, 0, 267589, 0, 3362251073, 0, 421424697891, 0, 38751520678991, 0, 44386209501802003, 0, 228891128457907983257, 0, 1636462395711601387189, 0, 348063222218272291910609213, 0, 3710225622968600411572814809525

Offset

0,9

Links

Table of n, a(n) for n=0..30.

Formula

a(n) = numerator(Bernoulli(n)^2*(2^(n+2) - 4)).

Example

Rational sequence starts: 0, 1, 1/3, 0, 1/15, 0, 1/7, 0, 17/15, 0, 775/33, 0, 477481/455, ...

Maple

a := s -> `if`(s = 0, 0, -4*s^2*Zeta(1 - s)^2*(1 - 2^s)):
seq(numer(a(s)), s = 0..24);

Crossrefs

Cf. A335265 (denominators), A164555/A027642 (Bernoulli numbers).

Cf. A335538, A335539, A327497.

Sequence in context: A198631 A185685 A144692 * A241027 A176728 A300909

Adjacent sequences: A335261 A335262 A335263 * A335265 A335266 A335267

Keyword

nonn,frac

Author

Peter Luschny, Jun 13 2020

Status

approved