id:A093518 - OEIS Search Results

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Number of ways of representing n as exactly 2 generalized pentagonal numbers.

+0
2

1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 0, 2, 1, 2, 1, 1, 2, 0, 1, 1, 0, 2, 1, 2, 0, 1, 3, 1, 1, 1, 1, 0, 1, 1, 1, 1, 2, 1, 0, 2, 2, 2, 0, 1, 1, 0, 2, 1, 0, 1, 1, 3, 1, 0, 1, 1, 2, 2, 1, 0, 1, 2, 1, 1, 0, 2, 0, 0, 1, 2, 1, 2, 1, 0, 2, 0, 3, 1, 2, 1, 0, 2, 1, 1, 1, 1, 0, 0, 1, 0, 1, 4, 1, 1, 0, 1, 2, 0, 2, 1, 1, 2, 1 (list; graph; listen)

	OFFSET	`0,3`
	EXAMPLE	`a(7)=2 as we have 7+0=5+2`
	PROGRAM	`(PARI) { v=vector(101); v[1]=0; for (i=1, 50, v[2i]=i(3i-1)/2; v[2i+1]=i(3i+1)/2); x=vector(500); for (a=1, 50, for (b=a, 50, if (v[a]+v[b]<500, x[v[a]+v[b]+1]++))); x }`
	CROSSREFS	`Cf. A001318 (generalized pentagonal numbers), A002107 (expansion of Product (1-x^k)^2, k=1..inf.), A093519 (A093518(n)=0).` `Sequence in context: A114171 A140345 A016024 this_sequence A128184 A025450 A139128` `Adjacent sequences: A093515 A093516 A093517 this_sequence A093519 A093520 A093521`
	KEYWORD	`nonn`
	AUTHOR	`Jon Perry (perry(AT)globalnet.co.uk), Mar 29 2004`

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.

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