OFFSET
0,8
LINKS
FORMULA
A(n,k) = Sum_{i=0..k} C(k,i) * A256069(n,i).
A(n,k) = Sum_{p,q in P(n)} k^Sum_{i in p, j in q} gcd(i, j) / (N(p)*N(q)) where N(p) = Product_{distinct parts x in p} x^m(x)*m(x)!, m(x) = multiplicity of x in p. - M. F. Hasler, Apr 30 2022 [corrected by Anders Kaseorg, Oct 04 2024]
EXAMPLE
Square array A(n,k) begins:
1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, ...
0, 1, 7, 27, 76, 175, ...
0, 1, 36, 738, 8240, 57675, ...
0, 1, 317, 90492, 7880456, 270656150, ...
0, 1, 5624, 64796982, 79846389608, 20834113243925, ...
MAPLE
b:= proc(n, i) option remember; `if`(n=0, [[]],
`if`(i<1, [], [b(n, i-1)[], seq(map(p->[p[], [i, j]],
b(n-i*j, i-1))[], j=1..n/i)]))
end:
A:= proc(n, k) option remember; add(add(k^add(add(i[2]*j[2]*
igcd(i[1], j[1]), j=t), i=s) /mul(i[1]^i[2]*i[2]!, i=s)
/mul(i[1]^i[2]*i[2]!, i=t), t=b(n$2)), s=b(n$2))
end:
seq(seq(A(n, d-n), n=0..d), d=0..10);
PROG
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Aug 13 2014
STATUS
approved