id:A133459 - OEIS Search Results

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Sums of two nonzero pentagonal pyramidal numbers.

+0
4

2, 7, 12, 19, 24, 36, 41, 46, 58, 76, 80, 81, 93, 115, 127, 132, 144, 150, 166, 197, 201, 202, 214, 236, 252, 271, 289, 294, 306, 322, 328, 363, 392, 406, 411, 414, 423, 445, 480, 484, 531, 551, 556, 568, 576, 590, 601, 625, 676, 693, 727, 732, 744, 746, 766 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Does this sequence ever include a pentagonal pyramidal number? That is, is it ever the case that A002411(i)=A002411(j)+A002411(k) as is often true for triangular pyramidal numbers (tetrahedral numbers) or square pyramidal numbers?`
	FORMULA	`{A002411(i) + A002411(j) for i, j > 0} = {i^2(i+1)/2 + j^2(j+1)/2 for i, j > 0}.`
	CROSSREFS	`Cf. A002311, A002411, A053721.` `Sequence in context: A019592 A131190 A099353 this_sequence A023669 A137401 A119713` `Adjacent sequences: A133456 A133457 A133458 this_sequence A133460 A133461 A133462`
	KEYWORD	`nonn`
	AUTHOR	`Jonathan Vos Post (jvospost2(AT)yahoo.com), Dec 23 2007`

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Last modified July 23 10:48 EDT 2008. Contains 142285 sequences.

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