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A045951 Number of solutions to product_A+product_B=product_C where A,B,C is a partition of {1,2,...n}. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 17 03:11 EDT 2022. Contains 356180 sequences. (Running on oeis4.)