id:A128549 - OEIS Search Results

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Difference between triangular number and next perfect square.

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3, 1, 3, 6, 1, 4, 8, 13, 4, 9, 15, 3, 9, 16, 1, 8, 16, 25, 6, 15, 25, 3, 13, 24, 36, 10, 22, 35, 6, 19, 33, 1, 15, 30, 46, 10, 26, 43, 4, 21, 39, 58, 15, 34, 54, 8, 28, 49, 71, 21, 43, 66, 13, 36, 60, 4, 28, 53, 79, 19, 45, 72, 9, 36, 64, 93, 26, 55, 85, 15, 45, 76, 3, 34, 66, 99, 22 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`a(n)=(floor(sqrt(n(n+1)/2))+1)^2-n(n+1)/2`
	EXAMPLE	`a(1)=2^2-1(1+1)/2=3, a(2)=2^2-2(2+1)/2=1, a(3)=3^2-3(3+1)/2=3, a(3)=4^2-4(4+1)/2=6.`
	MATHEMATICA	`Table[(Floor[Sqrt[n(n+1)/2]]+1)^2-n(n+1)/2, {n, 100}]`
	CROSSREFS	`Cf. A000217.` `Adjacent sequences: A128546 A128547 A128548 this_sequence A128550 A128551 A128552` `Sequence in context: A133179 A049324 A131111 this_sequence A055885 A096713 A107726`
	KEYWORD	`nonn`
	AUTHOR	`Zak Seidov (zakseidov(AT)yahoo.com), May 08 2007`

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

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