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 A174811 #10 Sep 08 2022 08:45:51
%S A174811 1,3,26,836,118304,56868928,77348401664,336344302104576,
%T A174811 6256170906514948096,461016146852019430227968,
%U A174811 101290253760680508433761304576,64552542594684734744030356172701696
%N A174811 A (100,-196) Somos 4 sequence.
%C A174811 Hankel transform of A174810.
%H A174811 G. C. Greubel, <a href="/A174811/b174811.txt">Table of n, a(n) for n = 0..60</a>
%F A174811 a(n) = (100*a(n-1)*a(n-3) - 196*a(n-2)^2)/a(n-4), n>3.
%t A174811 nxt[{a_,b_,c_,d_}]:={b,c,d,(100*d*b-196c^2)/a}; Transpose[ NestList[ nxt,{1,3,26,836},12]][[1]] (* _Harvey P. Dale_, Jun 20 2015 *)
%t A174811 RecurrenceTable[{a[n] == (100*a[n-1]*a[n-3] -196*a[n-2]^2)/a[n-4], a[0] == 1, a[1] == 3, a[2] == 26, a[3] == 836}, a, {n, 0, 30}] (* _G. C. Greubel_, Sep 25 2018 *)
%o A174811 (PARI) m=30; v=concat([1, 3, 26, 836], vector(m-4)); for(n=5, m, v[n] = ( 100*v[n-1]*v[n-3] - 196*v[n-2]^2)/v[n-4]); v \\ _G. C. Greubel_, Sep 25 2018
%o A174811 (Magma) I:=[1, 3, 26, 836]; [n le 4 select I[n] else (100*Self(n-1)*Self(n-3) - 196*Self(n-2)^2)/Self(n-4): n in [1..30]]; // _G. C. Greubel_, Sep 25 2018
%K A174811 easy,nonn
%O A174811 0,2
%A A174811 _Paul Barry_, Mar 29 2010