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 A385205 #15 Jun 21 2025 11:49:31 %S A385205 1,5,50,500,4375,27500,0,-3562500,-70078125,-876562500,-6926562500,0, %T A385205 1189169921875,25690820312500,346441406250000,2911880859375000,0, %U A385205 -550017993164062500,-12339622131347656250,-171953389892578125000,-1487552714691162109375,0 %N A385205 G.f. A(x) satisfies A(x) = ( 1 + 25*x*A(x)^4 )^(1/5). %F A385205 a(n) = 25^n * binomial(4*n/5+1/5,n)/(4*n+1). %F A385205 G.f. A(x) satisfies A(x) = 1/A(-x*A(x)^3). %F A385205 G.f.: ( (1/x) * Series_Reversion(x/(1+25*x)^(4/5)) )^(1/4). %F A385205 a(5*n+1) = 0 for n > 0. %F A385205 G.f.: 1/B(x), where B(x) is the g.f. of A299958. %o A385205 (PARI) a(n) = 25^n*binomial(4*n/5+1/5, n)/(4*n+1); %Y A385205 Cf. A078534, A299958, A385203, A385204. %Y A385205 Cf. A182122, A376636, A385207. %K A385205 sign %O A385205 0,2 %A A385205 _Seiichi Manyama_, Jun 21 2025