OFFSET
1,2
COMMENTS
See A368366 for further information.
FORMULA
a(n) ~ (n*(n+1)*(n+2)/6)^n - n^n*n!*(n+1)!/2^n. - Vaclav Kotesovec, Jan 24 2024
MATHEMATICA
Table[Sum[k*(k+1)/2, {k, 1, n}]^n - n^n*Product[k*(k+1)/2, {k, 1, n}], {n, 1, 12}] (* Vaclav Kotesovec, Jan 24 2024 *)
PROG
(Python)
from math import comb, factorial
def A368370(n): return comb(n+2, 3)**n-(n**n*factorial(n)**2*(n+1)>>n) # Chai Wah Wu, Jan 25 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 24 2024
STATUS
approved