OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..26
FORMULA
a(n) = Sum_{p in {1..n}^n : p_i <= p_{i+1}} Product_{j=1..n} p_j^n.
EXAMPLE
a(2) = (1*1)^2 + (1*2)^2 + (2*2)^2 = 1 + 4 + 16 = 21.
MAPLE
b:= proc(n, k, p) option remember; `if`(k=0, 1,
add(b(j, k-1, p)*j^p, j=1..n))
end:
a:= n-> b(n$3):
seq(a(n), n=0..9);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 19 2022
STATUS
approved