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 A144895 #8 Apr 05 2016 00:42:16 %S A144895 1,2,10,36,204,1104,7776,57600,505440,4803840,51442560,597784320, %T A144895 7609593600,104364288000,1541746483200,24329797632000,409042632499200, %U A144895 7290954768384000,137384159367168000,2727604332085248000,56913717580296192000,1244955414746824704000 %N A144895 Second column of triangle A134134 (S2'(2) = S1hat(2)). %C A144895 Sum of the products of the factorials of the partition parts of n+2 into two parts. - _Wesley Ivan Hurt_, Mar 18 2016 %F A144895 a(n) = A134134(n+2,2), n>=0. %F A144895 a(n) = Sum_{i=1..floor(n/2)+1} i! * (n-i+2)!. - _Wesley Ivan Hurt_, Mar 18 2016 %e A144895 a(2)=10; The partitions of (2)+2 = 4 into two parts are: (3,1) and (2,2). The sum of the products of the factorials of the partition parts is: 3!*1! + 2!*2! = 6 + 4 = 10. - _Wesley Ivan Hurt_, Mar 18 2016 %p A144895 A144895:=n->add(i!*(n-i+2)!, i=1..floor(n/2)+1): seq(A144895(n), n=0..30); # _Wesley Ivan Hurt_, Mar 18 2016 %t A144895 Table[Sum[i!*(n - i + 2)!, {i, Floor[n/2] + 1}], {n, 0, 20}] (* _Wesley Ivan Hurt_, Mar 18 2016 *) %Y A144895 Cf. A000142 (factorials, first column). A144896 (third column). %Y A144895 Cf. A134134. %K A144895 nonn,easy %O A144895 0,2 %A A144895 _Wolfdieter Lang_, Oct 09 2008