id:A074314 - OEIS Search Results

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Deficient triangular numbers.

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1, 3, 10, 15, 21, 45, 55, 91, 105, 136, 153, 171, 190, 231, 253, 325, 351, 406, 435, 465, 561, 595, 703, 741, 861, 903, 946, 1035, 1081, 1225, 1275, 1378, 1431, 1485, 1653, 1711, 1891, 1953, 2145, 2211, 2278, 2415, 2485, 2701, 2775, 2926, 3003, 3081, 3321 (list; graph; listen)

	OFFSET	`1,2`
	EXAMPLE	`a(5)=21 because sum of aliquot divisors of 21( which is a triangular number) is 1+3+7=11 which is less than 21, hence it is deficient. 21 is 5th deficient triangular number.`
	CROSSREFS	`Sequence in context: A134102 A108770 A112355 this_sequence A077759 A063231 A030005` `Adjacent sequences: A074311 A074312 A074313 this_sequence A074315 A074316 A074317`
	KEYWORD	`base,nonn`
	AUTHOR	`Shyam Sunder Gupta (guptass(AT)rediffmail.com), Sep 22 2002`

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.

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