id:A027669 - OEIS Search Results

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Numbers n such that for some m, the sum of the first m n-gonal numbers is again an n-gonal number.

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	OFFSET	`1,1`
	FORMULA	`k-th n-gonal number is k+(n-2)*(k^2-k)/2).`
	CROSSREFS	`Cf. A027696.` `Sequence in context: A024672 A091555 A024665 this_sequence A027696 A027440 A029902` `Adjacent sequences: A027666 A027667 A027668 this_sequence A027670 A027671 A027672`
	KEYWORD	`nonn`
	AUTHOR	`Masanobu Kaneko (mkaneko(AT)math.kyushu-u.ac.jp)`

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Last modified December 10 00:48 EST 2009. Contains 170565 sequences.

AT&T Labs Research