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A319817
Number of partitions of n into exactly seven positive triangular numbers.
5
1, 0, 1, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 4, 3, 3, 3, 4, 4, 6, 4, 5, 5, 7, 6, 6, 8, 7, 10, 8, 8, 10, 10, 11, 11, 12, 11, 14, 14, 13, 14, 16, 15, 17, 18, 17, 20, 19, 20, 21, 22, 21, 22, 27, 23, 28, 26, 26, 29, 31, 27, 31, 34, 34, 35, 34, 34, 37, 42, 37, 39, 42
OFFSET
7,10
LINKS
FORMULA
a(n) = [x^n y^7] 1/Product_{j>=1} (1-y*x^A000217(j)).
MAPLE
h:= proc(n) option remember; `if`(n<1, 0,
`if`(issqr(8*n+1), n, h(n-1)))
end:
b:= proc(n, i, k) option remember; `if`(n=0, `if`(k=0, 1, 0), `if`(
k>n or i*k<n, 0, b(n, h(i-1), k)+b(n-i, h(min(n-i, i)), k-1)))
end:
a:= n-> b(n, h(n), 7):
seq(a(n), n=7..120);
CROSSREFS
Column k=7 of A319797.
Cf. A000217.
Sequence in context: A260123 A319411 A164296 * A233566 A319818 A319819
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 28 2018
STATUS
approved