A144895 Second column of triangle A134134 (S2'(2) = S1hat(2)).
1, 2, 10, 36, 204, 1104, 7776, 57600, 505440, 4803840, 51442560, 597784320, 7609593600, 104364288000, 1541746483200, 24329797632000, 409042632499200, 7290954768384000, 137384159367168000, 2727604332085248000, 56913717580296192000, 1244955414746824704000
Offset: 0
Examples
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
Programs
-
Maple
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
-
Mathematica
Table[Sum[i!*(n - i + 2)!, {i, Floor[n/2] + 1}], {n, 0, 20}] (* Wesley Ivan Hurt, Mar 18 2016 *)
Formula
a(n) = A134134(n+2,2), n>=0.
a(n) = Sum_{i=1..floor(n/2)+1} i! * (n-i+2)!. - Wesley Ivan Hurt, Mar 18 2016
Comments