%I #8 Nov 21 2013 12:48:16
%S 0,5,17,195,4369,158875,8493081,626349395,60921163553,7555181167755,
%T 1163556514166185,217865966280741955,48740349457479955377,
%U 12839917161220487631995,3934089704476487908489529
%N a(n)=(-1)^(n+1)*2*(16^n-1)*B(2n) where B(k) denotes the k-th Bernoulli number.
%t Table[(-1)^(n+1) 2(16^n-1)BernoulliB[2n],{n,0,20}] (* _Harvey P. Dale_, Nov 10 2011 *)
%o (PARI) a(n)=(-1)^(n+1)*2*(16^n-1)*bernfrac(2*n)
%K nonn
%O 0,2
%A _Benoit Cloitre_, Dec 13 2003