id:A078777 - OEIS Search Results

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a(n) = the least positive integer k such that binomial(2k,k) + k + n is prime, if such k exists; = 0, otherwise.

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0, 1, 2, 1, 2, 3, 6, 1, 2, 1, 2, 5, 120, 1, 2, 1, 6, 3, 58, 1, 2, 7, 2, 3, 12, 1, 4, 1, 2, 3, 12, 9, 2, 1, 2, 3, 6, 1, 2, 1, 6, 19, 16, 1, 2, 13, 6, 3, 12, 1, 2, 7, 2, 5, 16, 1, 4, 1, 2, 3, 6, 15, 2, 1, 2, 3, 6, 1, 14, 1, 2, 7, 16, 3, 2, 1, 4, 3, 6, 1 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`The value a(1) = 0 is conjectural. There is no k < 8.5 x 10^3 such that binomial[2k,k]+k+1 is prime.`
	EXAMPLE	`k=2 is the least positive integer such that binomial(2k,k) + k + 3 is prime. Hence a(2) = 3.`
	CROSSREFS	`Sequence in context: A125596 A132405 A057192 this_sequence A135938 A079210 A070861` `Adjacent sequences: A078774 A078775 A078776 this_sequence A078778 A078779 A078780`
	KEYWORD	`nonn`
	AUTHOR	`Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 09 2003`

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Last modified December 9 18:50 EST 2009. Contains 170568 sequences.

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