id:A046193 - OEIS Search Results

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Indices of heptagonal numbers (A000566) which are also triangular.

+0
3

1, 5, 221, 1513, 71065, 487085, 22882613, 156839761, 7368130225, 50501915861, 2372515049741, 16261460067385, 763942477886281, 5236139639782013, 245987105364332645, 1686020702549740705, 79207083984837225313 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.`
	FORMULA	`For n odd, a(n+2)=322a(n+1)-a(n)-96; for n even, a(n+1)=161a(n)-48+36(20a(n)^2-12*a(n)+1)^0.5 - Richard Choulet (richardchoulet(AT)yahoo.fr), Sep 29 2007, Oct 09 2007`
	CROSSREFS	`Cf. A039835, A046194.` `Cf. A039835 A046194.` `Sequence in context: A024070 A050617 A066462 this_sequence A112999 A002142 A103732` `Adjacent sequences: A046190 A046191 A046192 this_sequence A046194 A046195 A046196`
	KEYWORD	`nonn`
	AUTHOR	`Eric Weisstein (eric(AT)weisstein.com)`

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Last modified December 4 15:11 EST 2009. Contains 170347 sequences.

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