A118139 - OEIS

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A118139

Numbers expressible as the sum of two triangular numbers in at least two different ways.

6, 16, 21, 31, 36, 42, 46, 51, 55, 56, 66, 72, 76, 81, 91, 94, 106, 111, 120, 121, 123, 126, 133, 136, 141, 146, 156, 157, 171, 172, 174, 181, 186, 191, 196, 198, 210, 211, 216, 225, 226, 231, 237, 241, 246, 256, 259, 268, 276, 281, 286, 289, 291, 297, 301, 306 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`A052343(a(n)) > 1; gives A020756 together with A119345. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 15 2006`
	EXAMPLE	`a(1) = 6 = 0 + 6 = 3 +3.` `a(2) = 16 = 1 + 15 = 6 + 10.` `a(3) = 21 = 0 + 21 = 6 + 15.`
	CROSSREFS	`Cf. A020757, A000217.` `Sequence in context: A101239 A104392 A037001 * A087446 A051808 A034053` `Adjacent sequences: A118136 A118137 A118138 * A118140 A118141 A118142`
	KEYWORD	`easy,nonn`
	AUTHOR	`Greg Huber (huber(AT)alum.mit.edu), May 13 2006`
	EXTENSIONS	`More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 15 2006`

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Last modified February 15 21:27 EST 2012. Contains 205859 sequences.