OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..30
G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 331997
FORMULA
EXAMPLE
a(1) = (1!)^1 = 1^1 = 1.
a(2) = (1!)^1 + (2!)^2 = 1^1 + 2^2 = 1 + 4 = 5.
a(3) = (1!)^1 + (2!)^2 + (3!)^3 = 1^1 + 2^2 + 6^3 = 1 + 4 + 216 = 221.
MATHEMATICA
Table[Sum[Product[m^k, {m, 1, k}], {k, 1, n}], {n, 1, 10}] (* Vaclav Kotesovec, Nov 01 2014 *)
Accumulate[Table[(n!)^n, {n, 10}]] (* Harvey P. Dale, Dec 23 2019 *)
PROG
(PARI) a(n) = sum(k=1, n, k!^k); \\ Michel Marcus, Nov 30 2020
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jan 03 2006
STATUS
approved