id:A112355 - OEIS Search Results

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Triangular numbers that are the sum of three positive triangular numbers.

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3, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 666, 703, 741, 780, 820, 861, 903, 946, 990, 1035, 1081, 1128, 1176, 1225, 1275, 1326 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`A112353 is a subsequence: it requires the three positive triangular numbers to be distinct. The positive terms of A076140 are a subsequence.`
	EXAMPLE	`21 is a term because 21 = 3 + 3 + 15 and these four numbers are positive triangular numbers (A000217(6) = A000217(2) + A000217(2) + A000217(5)). {Also 21 = 1 + 10 + 10 = A000217(1) + A000217(4) + A000217(4).}.`
	CROSSREFS	`Cf. A000217 (triangular numbers), A089982 (triangular numbers that are the sum of two positive triangular numbers), A112353, A076140 (the three triangular numbers summed are identical).` `Sequence in context: A141463 A134102 A108770 this_sequence A074314 A077759 A063231` `Adjacent sequences: A112352 A112353 A112354 this_sequence A112356 A112357 A112358`
	KEYWORD	`nonn`
	AUTHOR	`Rick L. Shepherd (rshepherd2(AT)hotmail.com), Sep 06 2005`

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Last modified March 20 01:21 EDT 2010. Contains 173643 sequences.

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