login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

a(n) = denominator(b(2*n)) with b(n) = n!*Bernoulli(n,1/2)/(n*(n-1)) for n>=2, b(0)=1, b(1)=0.
2

%I #6 Sep 25 2016 04:00:02

%S 1,12,120,56,16,88,208,16,544,152,16,368,32,16,928,992,64,8,592,16,

%T 1312,688,32,1504,64,16,1696,32,64,1888,3904,64,128,536,16,1136,2336,

%U 16,32,2528,64,1328,32,32,5696,32,64,64,12416,16,3232,3296,64,3424,6976

%N a(n) = denominator(b(2*n)) with b(n) = n!*Bernoulli(n,1/2)/(n*(n-1)) for n>=2, b(0)=1, b(1)=0.

%p b := n -> `if`(n<2, 1-n, (n-2)!*bernoulli(n,1/2)):

%p a := n -> denom(b(2*n)):

%p seq(a(n), n=0..54);

%Y Cf. A276667 (numerators).

%K nonn,frac

%O 0,2

%A _Peter Luschny_, Sep 24 2016