This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A237425 #15 Feb 17 2014 23:47:41
%S A237425 1,1,6,4,30,2,42,8,30,2,66,4,2730,2,6,16,510,2,798,4,330,2,138,8,2730,
%T A237425 2,6,4,870,2,14322,32,510,2,6,4,1919190,2,6,8,13530,2,1806,4,690,2,
%U A237425 282,16,46410,2,66,4,1590,2,798,8
%N A237425 Denominators of A164555(n)/A027642(n) + A198631(n)/A006519(n+1).
%C A237425 An autosequence is a sequence which has its inverse binomial transform equal to the signed sequence. There are two possibilities. For the first kind, the main diagonal is 0's=A000004, the first two following diagonals being the same (generally not A000004). Integers example: A000045(n).
%C A237425 For the second kind, the main diagonal is the double of the following diagonal. Example: the companion to A000045(n) is A000032(n)=2, 1, 3, ... .
%C A237425 A000032(n)/2 is also a possibility. Here a(n) is the denominator of the sum of two autosequences of second kind involving (fractional) Euler and Bernoulli numbers. The corresponding fractional sequence is also an autosequence of the second kind: 2, 1, 1/6, -1/4, -1/30, 1/2, 1/42, -17/8, -1/30, 31/2, 5/66, -691/4, -691/2730,... . It could be divided by 2.
%F A237425 a(2n) = A002445(n). a(2n+2) = A171977(n+2).
%t A237425 a[n_] := BernoulliB[n] + EulerE[n, 1]/2^IntegerExponent[n, 2]; a[0] = 2; a[1] = 1; Table[a[n] // Denominator, {n, 0, 55}] (* _Jean-François Alcover_, Feb 11 2014 *)
%Y A237425 Cf. 1/n in A003506, A194767, A218289, A168516/A168426, A224270/A046161.
%K A237425 nonn
%O A237425 0,3
%A A237425 _Paul Curtz_, Feb 07 2014