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 A162993 #7 Apr 01 2024 13:44:51 %S A162993 9,144,3600,129600,6350400,406425600,32920473600,3292047360000, %T A162993 398337730560000,57360633200640000,9693947010908160000, %U A162993 1900013614137999360000,427503063181049856000000,109440784174348763136000000,31628386626386792546304000000 %N A162993 The second left hand column of triangle A162990. %F A162993 a(n) = ((n+1)!/2)^2 for n = 2, 3, ... . %F A162993 a(n) = A001710(n+1)^2. %t A162993 Array[((#+1)!/2)^2 &, 20, 2] (* _Paolo Xausa_, Apr 01 2024 *) %Y A162993 A001044 and A162994 are two other left hand columns. %Y A162993 A001710(n+1) equals the square root of a(n). %K A162993 easy,nonn %O A162993 2,1 %A A162993 _Johannes W. Meijer_, Jul 21 2009