id:A072943 - OEIS Search Results

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Least nonnegative integer k such that n + k^3 is prime, or -1 if no such k exists.

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1, 0, 0, 1, 0, 1, 0, -1, 2, 1, 0, 1, 0, 3, 2, 1, 0, 1, 0, 3, 2, 1, 0, 5, 4, 3, -1, 1, 0, 1, 0, 3, 2, 3, 2, 1, 0, 5, 2, 1, 0, 1, 0, 3, 2, 1, 0, 5, 4, 11, 2, 1, 0, 5, 6, 3, 8, 1, 0, 1, 0, 3, 2, -1, 2, 1, 0, 5, 10, 1, 0, 1, 0, 3, 2, 3, 6, 1, 0, 3, 2, 1, 0, 13, 4, 3, 4, 1, 0, 7, 6, 9, 2, 9, 2, 1, 0, 5, 2, 1 (list; graph; listen)

	OFFSET	`1,9`
	COMMENT	`For n = 2^3, 3^3, 4^3,...., a(n) = -1 since, say, 2^3 + k^3 cannot be prime for nonnegative k (it can be factored by the sum of cubes formula).`
	EXAMPLE	`a(9) = 2 since k = 2 is the least nonnegative integer such that 9 + k^3 is prime.`
	CROSSREFS	`Sequence in context: A144152 A116675 A123022 this_sequence A072175 A092147 A143240` `Adjacent sequences: A072940 A072941 A072942 this_sequence A072944 A072945 A072946`
	KEYWORD	`sign`
	AUTHOR	`Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Aug 14 2002`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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