id:A061782 - OEIS Search Results

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Smallest number such that n*a(n) is a triangular number.

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1, 3, 1, 7, 2, 1, 3, 15, 4, 1, 5, 3, 6, 2, 1, 31, 8, 2, 9, 6, 1, 3, 11, 5, 12, 3, 13, 1, 14, 4, 15, 63, 2, 4, 3, 1, 18, 5, 2, 3, 20, 5, 21, 12, 1, 6, 23, 11, 24, 6, 3, 15, 26, 7, 1, 21, 3, 7, 29, 2, 30, 8, 6, 127, 5, 1, 33, 2, 4, 3, 35, 28, 36, 9, 4, 21, 3, 1, 39, 26, 40, 10, 41, 14, 7, 11, 5 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`Matthew M. Conroy, Home page (listed instead of email address)`
	FORMULA	`For p an odd prime, a(p) = (p-1)/2. For nonnegative k, a(2^k) = 2^(k+1)-1.` `Formula corrected by Nick Singer, Jun 26 2006`
	EXAMPLE	`a(4) = 7 as 4*7 = 28 is a triangular number and 7 is the smallest such number.`
	CROSSREFS	`Adjacent sequences: A061779 A061780 A061781 this_sequence A061783 A061784 A061785` `Sequence in context: A089741 A089736 A094024 this_sequence A074625 A091724 A016576`
	KEYWORD	`nonn,easy`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 24 2001`
	EXTENSIONS	`Corrected and extended by Matthew M. Conroy, May 28 2001`

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Last modified May 16 23:01 EDT 2008. Contains 139884 sequences.

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