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 A386273 #10 Jul 20 2025 14:42:00
%S A386273 1,28,1078,45276,1980825,88740960,4037713680,185734829280,
%T A386273 8613452707860,401961126366800,18851976826602920,887756726925482960,
%U A386273 41946505347229069860,1987619022607162079520,94411903573840198777200,4494006610114793461794720,214307940219849213209335710
%N A386273 Expansion of 1/(1 - 49*x)^(4/7).
%F A386273 a(n) = (-49)^n * binomial(-4/7,n).
%F A386273 a(n) = 7^n/n! * Product_{k=0..n-1} (7*k+4).
%F A386273 a(n) = 7^n * Product_{k=1..n} (7 - 3/k).
%F A386273 D-finite with recurrence n*a(n) +7*(-7*n+3)*a(n-1)=0. - _R. J. Mathar_, Jul 20 2025
%o A386273 (PARI) my(N=20, x='x+O('x^N)); Vec(1/(1-49*x)^(4/7))
%Y A386273 Cf. A034835, A216703, A386271, A386272, A386274.
%K A386273 nonn,easy
%O A386273 0,2
%A A386273 _Seiichi Manyama_, Jul 17 2025