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 A381161 #9 Feb 16 2025 04:40:29 %S A381161 1,15120,3491888400,1304290155168000,601680868708529610000, %T A381161 312696069714024464473125120,175460887238127057573116837126400, %U A381161 103865765423748548466734695459219968000,63958974275578307119821712720619705931210000,40596987692554701292235753375257230410967703200000 %N A381161 a(n) = (10*n)!/((n!)^3*(2*n)!*(5*n)!). %C A381161 Calabi-Yau series number 2. %H A381161 S. Hassani, J-M. Maillard, and N. Zenine, <a href="https://arxiv.org/abs/2502.05543">On the diagonals of rational functions: the minimal number of variables (unabridged version)</a>, arXiv:2502.05543 [math-ph], 2025. See p. 14. %F A381161 G.f.: hypergeom([1/10, 3/10, 7/10, 9/10], [1, 1, 1], 2^8*5^5*x). %F A381161 a(n) ~ 9*2^(3+8*n)*5^(1+5*n)/((1 + 24*n)*(1 + 60*n)*Pi^2). %t A381161 a[n_]:=(10n)!/((n!)^3*(2n)!*(5n)!); Array[a,10,0] %Y A381161 Cf. A000442, A010050, A100734, A195394. %Y A381161 Cf. A381162, A381163, A381164, A381165. %K A381161 nonn %O A381161 0,2 %A A381161 _Stefano Spezia_, Feb 15 2025