|
|
A091348
|
|
a(n) = 24*5^n - 60*4^n + 50*3^n - 15*2^n + 1.
|
|
3
|
|
|
0, 1, 31, 391, 3451, 25231, 164731, 999391, 5767051, 32122831, 174397531, 929043391, 4879252651, 25349936431, 130617150331, 668714319391, 3406562690251, 17286209766031, 87448932863131, 441329102667391, 2223021985199851, 11180731992411631, 56166496811775931, 281884877304327391
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
FORMULA
|
a(n) = Sum_{i=1..n} i!*i^4*Stirling2(n, i)*(-1)^(n-i).
|
|
MATHEMATICA
|
Table[24*5^n - 60*4^n + 50*3^n - 15*2^n + 1, {n, 0, 25}]
|
|
PROG
|
(PARI) a(n) = sum(i=1, n, i!*i^4*stirling(n, i, 2)*(-1)^(n-i)); \\ Michel Marcus, Oct 21 2022
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
Mario Catalani (mario.catalani(AT)unito.it), Jan 03 2004
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|