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 A380465 #23 Jun 23 2025 10:12:48 %S A380465 1,5,125,4250,166250,7052500,315459375,14648437500,699404062500, %T A380465 34120414453125,1693355782421875,85222795492187500, %U A380465 4339218139648437500,223115431527734375000,11568972340119140625000,604249120575386718750000,31761084429202554931640625,1678825356066226959228515625 %N A380465 G.f. A(x) satisfies A(x) = 1/( 1 - 25*x*A(x)^2 )^(1/5). %F A380465 G.f. A(x) satisfies A(x) = ( 1 + 25*x*A(x)^7 )^(1/5). %F A380465 a(n) = 25^n * binomial(7*n/5+1/5,n)/(7*n+1). %F A380465 G.f. A(x) satisfies A(x) = 1/A(-x*A(x)^9). %F A380465 G.f.: ( (1/x) * Series_Reversion(x/(1+25*x)^(7/5)) )^(1/7). %o A380465 (PARI) a(n) = 25^n*binomial(7*n/5+1/5, n)/(7*n+1); %Y A380465 Cf. A034688, A078534, A385203, A385204, A385205, A380466, A380471. %K A380465 nonn %O A380465 0,2 %A A380465 _Seiichi Manyama_, Jun 23 2025