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 A277354 #20 Oct 11 2016 03:24:34
%S A277354 1,5,85,3145,204425,20646925,2993804125,589779412625,151573309044625,
%T A277354 49261325439503125,19753791501240753125,9580588878101765265625,
%U A277354 5527999782664718558265625,3742455852864014463945828125,2937827844498251354197475078125
%N A277354 a(n) = Product_{k=1..n} (4*k^2+1).
%C A277354 In general, for m>0, Product_{k=1..n} (m*k^2+1) is asymptotic to 2*m^(n+1/2) * n^(2*n+1) * sinh(Pi/sqrt(m)) / exp(2*n).
%F A277354 a(n) = (-1)^(n+1) * A101928(n+2).
%F A277354 a(n) ~ 2^(2*n+2) * n^(2*n+1) * sinh(Pi/2) / exp(2*n).
%F A277354 a(n) = 2^(2*n+1) * |Gamma(1 + i/2 + n)|^2 * sinh(Pi/2)/Pi. - _Vladimir Reshetnikov_, Oct 10 2016
%t A277354 Table[Product[4*k^2+1, {k, 1, n}], {n, 0, 15}]
%t A277354 Round@Table[2^(2 n + 1) Abs[Gamma[1 + I/2 + n]]^2 Sinh[Pi/2]/Pi, {n, 0, 15}] (* _Vladimir Reshetnikov_, Oct 10 2016 *)
%o A277354 (PARI) a(n) = prod(k=1, n, (4*k^2+1)); \\ _Michel Marcus_, Oct 11 2016
%Y A277354 Cf. A079484, A101686, A101928, A274306, A277352, A277353.
%K A277354 nonn
%O A277354 0,2
%A A277354 _Vaclav Kotesovec_, Oct 10 2016