A280782 - OEIS

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A280782

Number of irreducible matrices X of all sizes with nonnegative integral entries satisfying X^2 = nX.

1, 2, 6, 15, 42, 99, 262, 633, 1592, 3897, 9697, 23767, 58804, 144541 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,2`
	LINKS	`Table of n, a(n) for n=1..14.` `Jakob Zimmermann, Counting quasi-idempotent irreducible integral matrices, arXiv:1701.03699 [math.CO], 2017.`
	CROSSREFS	`Cf. A280783.` `Sequence in context: A121328 A139379 A236110 * A307308 A065178 A178936` `Adjacent sequences: A280779 A280780 A280781 * A280783 A280784 A280785`
	KEYWORD	`nonn,more`
	AUTHOR	`N. J. A. Sloane, Jan 20 2017`
	EXTENSIONS	`Definition corrected by N. J. A. Sloane, Jan 23 2017 at the suggestion of Jakob Zimmermann` `a(14) from Jakob Zimmermann, Jan 23 2017`
	STATUS	`approved`

Last modified March 4 01:48 EST 2021. Contains 341773 sequences. (Running on oeis4.)