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 A091756 #10 Aug 30 2025 02:43:04 %S A091756 1,220,48720,14463680,5762556800,3000655257600,1987324218880000, %T A091756 1634736979972096000,1636859558116823040000,1961447726093804748800000, %U A091756 2772502956616965206835200000,4565871212782705024303104000000,8667353356325850744087642112000000,18789301668434870837372923150336000000 %N A091756 Seventh column (m=8) of array A091752 ((-1,2)Stirling2). %F A091756 a(n) = A091752(n, 8), n>=4. %F A091756 a(n) = (9/6!)*(n-3)*(9*n^3-45*n^2+36*n+40)*(3*(n-3))!/((3^(n-3))*(n-3)!) = (9/6!)*(n-3)*(9*n^3-45*n^2+36*n+40) * A052502(n-3), n>=4. %F A091756 a(n) ~ 3^(2*n-7/2) * n^(2*n-2) /(80 * exp(2*n-12/n)). - _Amiram Eldar_, Aug 30 2025 %t A091756 a[n_] := (9/6!)*(n-3)*(9*n^3 - 45*n^2 + 36*n + 40)*(3*(n-3))!/((3^(n-3))*(n-3)!); Array[a, 15, 4] (* _Amiram Eldar_, Aug 30 2025 *) %Y A091756 Cf. A052502, A091752. %K A091756 nonn,easy,changed %O A091756 4,2 %A A091756 _Wolfdieter Lang_, Feb 27 2004