A045951 Number of solutions to product_A+product_B=product_C where A,B,C is a partition of {1,2,...n}.

0, 1, 1, 0, 1, 1, 1, 1, 3, 4, 0, 0, 0, 0, 2, 0, 0, 0, 15, 42, 0, 113, 0, 3, 0

Offset

1,9

Links

Table of n, a(n) for n=1..25.

Sean A. Irvine, Java program (github)

Example

a(9)=3 since (1 2 6 7)+(4 9)=(3 5 8) and (1 3 4 8 )+(5 6)=(2 7 9) and (1 2 6)+(3 7 8)=(4 5 9).

Crossrefs

Sequence in context: A264932 A171604 A132139 * A238797 A025120 A025096

Adjacent sequences: A045948 A045949 A045950 * A045952 A045953 A045954

Keyword

hard,nonn

Author

Erich Friedman

Extensions

More terms from David W. Wilson.

a(21)-a(25) from Sean A. Irvine, Mar 28 2021

Status

approved