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 A375260 #19 Aug 08 2024 08:30:27
%S A375260 1,4,30,140,665,2856,11844,47160,182655,690580,2560558,9337692,
%T A375260 33573995,119246960,419034360,1458687312,5035531563,17253821340,
%U A375260 58723235970,198655153620,668338862499,2237229875496,7454611712100,24734393119800,81748883914425
%N A375260 Expansion of (1 - 3*x + 9*x^2 - 7*x^3)/(1 - 2*x - 3*x^2)^(7/2).
%H A375260 Seiichi Manyama, <a href="/A375260/b375260.txt">Table of n, a(n) for n = 0..1000</a>
%F A375260 a(n) = binomial(n+3,3) * Sum_{k=0..floor(n/2)} binomial(n,n-2*k) * binomial(2*k,k).
%F A375260 a(n) = binomial(n+3,3) * A002426(n).
%F A375260 a(n) = A132885(n+6,3).
%F A375260 a(n) = ((n+3)/n^2) * ((2*n-1)*a(n-1) + 3*(n+2)*a(n-2)).
%o A375260 (PARI) my(N=30, x='x+O('x^N)); Vec((1-3*x+9*x^2-7*x^3)/(1-2*x-3*x^2)^(7/2))
%Y A375260 Cf. A374506, A375248, A375253.
%Y A375260 Cf. A002426, A132885, A375259.
%K A375260 nonn
%O A375260 0,2
%A A375260 _Seiichi Manyama_, Aug 08 2024