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 A346766 #9 Aug 03 2021 15:04:08 %S A346766 1,1,6,51,531,6331,83532,1195452,18316582,297727712,5099398853, %T A346766 91554269703,1715910362408,33457504204403,676778172939139, %U A346766 14168046060375184,306327815585165519,6827996259530724139,156654003923243040925,3694188118839057258940,89428870506038692255920 %N A346766 a(n) = Sum_{k=0..n} Stirling2(n,k) * binomial(5*k,k) / (4*k + 1). %C A346766 Stirling transform of A002294. %F A346766 G.f.: Sum_{k>=0} ( binomial(5*k,k) / (4*k + 1) ) * x^k / Product_{j=0..k} (1 - j*x). %t A346766 Table[Sum[StirlingS2[n, k] Binomial[5 k, k]/(4 k + 1), {k, 0, n}], {n, 0, 20}] %t A346766 nmax = 20; CoefficientList[Series[Sum[(Binomial[5 k, k]/(4 k + 1)) x^k/Product[1 - j x, {j, 0, k}], {k, 0, nmax}], {x, 0, nmax}], x] %t A346766 nmax = 20; CoefficientList[Series[HypergeometricPFQ[{1/5, 2/5, 3/5, 4/5}, {1/2, 3/4, 1, 5/4}, 3125 (Exp[x] - 1)/256], {x, 0, nmax}], x] Range[0, nmax]! %o A346766 (PARI) a(n) = sum(k=0, n, stirling(n, k, 2)*binomial(5*k, k)/(4*k + 1)); \\ _Michel Marcus_, Aug 03 2021 %Y A346766 Cf. A002294, A064856, A346764, A346765, A346767, A346768, A346769. %K A346766 nonn %O A346766 0,3 %A A346766 _Ilya Gutkovskiy_, Aug 02 2021