id:A081950 - OEIS Search Results

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A081950

Smallest triangular number k such that k-1 has exactly n (not necessarily distinct) prime factors.

+0
2

3, 10, 21, 55, 253, 325, 1081, 4753, 8001, 18145, 226801, 293761, 7378561, 1181953, 33566721, 184291201, 471905281, 75479041, 924908545, 4831985665, 8590131201, 137438167041, 146163916801 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`a(4) = 233*3+1 = 55.`
	CROSSREFS	`Cf. A081951.` `Sequence in context: A007687 A006308 A008837 this_sequence A071563 A139116 A120109` `Adjacent sequences: A081947 A081948 A081949 this_sequence A081951 A081952 A081953`
	KEYWORD	`nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 02 2003`
	EXTENSIONS	`Extended and edited by Ryan Propper (rpropper(AT)stanford.edu), Jun 21 2005`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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