id:A067721 - OEIS Search Results

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Least number k such that k (k + n) is a perfect square, or 0 if impossible.

+0
5

1, 0, 0, 1, 0, 4, 2, 9, 1, 3, 8, 25, 4, 36, 18, 1, 2, 64, 6, 81, 16, 4, 50, 121, 1, 20, 72, 9, 36, 196, 2, 225, 4, 11, 128, 1, 12, 324, 162, 13, 5, 400, 8, 441, 100, 3, 242, 529, 1, 63, 40, 17, 144, 676, 18, 9, 7, 19, 392, 841, 4, 900, 450, 12, 8, 16, 22, 1089, 256, 23, 2, 1225 (list; graph; listen)

	OFFSET	`0,6`
	COMMENT	`Impossible only for 1, 2, and 4. k equals 1 when n is in A005563. k equals 2 when n is in A054000.`
	EXAMPLE	`a(7) = 9 because 9 (7+9) = 144 = 12^2.`
	MATHEMATICA	`Do[k = 1; While[ !IntegerQ[ Sqrt[ k (k + n)]], k++ ]; Print[k], {n, 5, 75} ]`
	CROSSREFS	`Cf. A067632.` `Adjacent sequences: A067718 A067719 A067720 this_sequence A067722 A067723 A067724` `Sequence in context: A016696 A127470 A010649 this_sequence A021237 A115881 A077809`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 05 2002`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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