login
a(n) = denominator(denominator(Bernoulli''(n, x)) / denominator(Bernoulli(n, 1))).
3

%I #10 Oct 14 2023 13:12:37

%S 1,2,6,1,30,1,42,1,10,1,66,1,2730,1,2,1,510,1,798,1,110,1,138,1,546,1,

%T 2,1,870,1,14322,1,170,1,6,1,1919190,1,2,1,13530,1,1806,1,46,1,282,1,

%U 1326,1,22,1,1590,1,798,1,290,1,354,1,56786730,1,2,1,102,1

%N a(n) = denominator(denominator(Bernoulli''(n, x)) / denominator(Bernoulli(n, 1))).

%F a(n) = denominator(A366168(n) / A027642(n)).

%p seq(denom(denom(diff(diff(bernoulli(n, x), x),x))/denom(bernoulli(n, 1))), n = 0..65);

%o (PARI) a(n) = denominator(lcm(apply(denominator, Vec(deriv(deriv(bernpol(n))))))/denominator(subst(bernpol(n, x), x, 1))); \\ _Michel Marcus_, Oct 14 2023

%Y Cf. A366168/A027642, A366426 (numerator), A366570/A366152 (1st derivative).

%K nonn,frac

%O 0,2

%A _Peter Luschny_, Oct 13 2023