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 A346543 #33 Oct 16 2021 11:39:55
%S A346543 1,10,1974,1234948,1601489318,3541644282540,11934462103156540,
%T A346543 56947950742822581960,365458809637016986262790,
%U A346543 3035813466162156094097686300,31694033885101849517370941522644,406222401519003083851664224927890360,6271146756206887832796744632163811733084
%N A346543 a(n) = [x^n] Product_{k=1..2*n} (x + (2*k-1)^2).
%F A346543 a(n) = A008956(2*n,n).
%F A346543 a(n) = (4*n+1)! * [x^(4*n+1)] (1/(2*n+1)!) * (arcsin(x))^(2*n+1).
%F A346543 a(n) ~ c * d^n * n!^2 / n^(3/2), where d = 121.8904568356133798202328777176879971969471503678428704459083316116687149... and c = 0.1081647814943965981694666415038643176470488612855594762896553127... - _Vaclav Kotesovec_, Oct 16 2021
%e A346543 (1/3!) * (arcsin(x))^3 = x^3/3! + 10 * x^5/5! + ... . So a(1) =10.
%e A346543 (1/5!) * (arcsin(x))^5 = x^5/5! + 35 * x^7/7! + 1974 * x^9/9! + ... . So a(2) = 1974.
%t A346543 Table[SeriesCoefficient[Product[(x + (2*k-1)^2), {k, 1, 2*n}], {x, 0, n}], {n, 0, 20}] (* _Vaclav Kotesovec_, Oct 16 2021 *)
%o A346543 (PARI) a(n) = polcoef(prod(k=1, 2*n, x+(2*k-1)^2), n);
%Y A346543 Cf. A008956, A016754, A234324, A293318.
%K A346543 nonn
%O A346543 0,2
%A A346543 _Seiichi Manyama_, Sep 27 2021