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 A091755 #9 Aug 30 2025 02:43:07 %S A091755 1,140,27720,7847840,3049446400,1564366003200,1026108219136000, %T A091755 838477001922560000,835580445006827520000,997744946185930342400000, %U A091755 1406513375677181496524800000,2311431202054422682730496000000,4380418953582248141850148864000000,9483101601549384660012281888768000000 %N A091755 Sixth column (m=7) of array A091752 ((-1,2)Stirling2) divided by -12. %F A091755 a(n) = -A091752(n, 7)/12, n>=4. %F A091755 a(n) = (3/(4*5!))*n*(n-3)*(3*(n-2))!/((3^(n-2))*(n-2)!) = 3*n*(n-3) * A052502(n-2)/(4*5!), n>=4. %F A091755 G.f.: (x^4)*hypergeom([7/3, 8/3, 5, 2], [4], 9*x). %F A091755 a(n) ~ 3^(2*n-7/2) * n^(2*n-2) /(160 * exp(2*n-5/n)). - _Amiram Eldar_, Aug 30 2025 %t A091755 a[n_] := (3/(4*5!))*n*(n-3)*(3*(n-2))!/((3^(n-2))*(n-2)!); Array[a, 15, 4] (* _Amiram Eldar_, Aug 30 2025 *) %Y A091755 Cf. A052502, A091752. %K A091755 nonn,easy,changed %O A091755 4,2 %A A091755 _Wolfdieter Lang_, Feb 27 2004