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 A277436 #7 Feb 16 2025 08:33:36
%S A277436 1,2,5,34,569,14426,518557,25400810,1625695409,131681938834,
%T A277436 13168189962101,1593350918236562,229442532743676265,
%U A277436 38775788044161003434,7600054456561351409549,1710012252724103327072026,437763136697393060993682017,126513546505547193228474910370
%N A277436 a(n) = |Gamma(n, i)|^2, where i = sqrt(-1).
%H A277436 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/IncompleteGammaFunction.html">Incomplete Gamma Function</a>
%F A277436 a(n) = |Gamma(n, i)|^2 = Gamma(n, i)*Gamma(n, -i), where i = sqrt(-1).
%F A277436 a(n) = A009102(n-1)^2 + A009551(n-1)^2.
%F A277436 Recurrence: n*(n-1)*(a(n-1) - (n-2)^2*a(n-2) + 1) + a(n+1) = n^2*a(n) + 1.
%F A277436 a(n) ~ (n-1)!^2. - _Vaclav Kotesovec_, Oct 15 2016
%t A277436 RecurrenceTable[{n (n - 1) (a[n - 1] - (n - 2)^2 a[n - 2] + 1) + a[n + 1] == n^2 a[n] + 1, a[1] == 1, a[2] == 2, a[3] == 5}, a[n], {n, 1, 20}] (* or *)
%t A277436 Round[Abs[Gamma[Range[20], I]]^2]
%Y A277436 Cf. A009102, A009551.
%K A277436 nonn
%O A277436 1,2
%A A277436 _Vladimir Reshetnikov_, Oct 14 2016