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 A162546 #10 Sep 08 2022 08:45:46
%S A162546 1,1,-16,-644,-40592,-4821056,17059328,2492895195136,
%T A162546 10659285907800064,86296767700623425536,1081586547380924161458176,
%U A162546 -36649408809924048998874742784,-18144416387824430577315746611724288
%N A162546 A Somos-4 variant: a(n) = (36*a(n-1)*a(n-3) - 68*a(n-2)^2)/a(n-4).
%C A162546 Hankel transform of A162543, A162548.
%H A162546 Fung Lam, <a href="/A162546/b162546.txt">Table of n, a(n) for n = 0..67</a>
%t A162546 RecurrenceTable[{a[n]==(36*a[n-1]*a[n-3] - 68*a[n-2]^2)/a[n-4], a[0]==1, a[1]==1, a[2]==-16, a[3]==-644}, a, {n,20}] (* _G. C. Greubel_, Feb 23 2019 *)
%o A162546 (PARI) m=20; v=concat([1,1,-16,-644], vector(m-4)); for(n=5, m, v[n] = (36*v[n-1]*v[n-3] -68*v[n-2]^2)/v[n-4]); v \\ _G. C. Greubel_, Feb 23 2019
%o A162546 (Magma) I:=[1,1,-16,-644]; [n le 4 select I[n] else (36*Self(n-1) *Self(n-3) - 68*Self(n-2)^2)/Self(n-4): n in [1..20]]; // _G. C. Greubel_, Feb 23 2019
%o A162546 (Sage)
%o A162546 def a(n):
%o A162546 if (n==0): return 1
%o A162546 elif (n==1): return 1
%o A162546 elif (n==2): return -16
%o A162546 elif (n==3): return -644
%o A162546 else: return (36*a(n-1)*a(n-3) - 68*a(n-2)^2)/a(n-4)
%o A162546 [a(n) for n in (1..20)] # _G. C. Greubel_, Feb 23 2019
%o A162546 (GAP) a:=[1,1,-16,-644];; for n in [5..20] do a[n]:=(36*a[n-1]*a[n-3] - 68*a[n-2]^2)/a[n-4]; od; a; # _G. C. Greubel_, Feb 23 2019
%Y A162546 Cf. A157005, A157101, A162547.
%K A162546 easy,sign
%O A162546 0,3
%A A162546 _Paul Barry_, Jul 05 2009