id:A081324 - OEIS Search Results

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Twice a square but not the sum of 2 distinct squares.

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0, 2, 8, 18, 32, 72, 98, 128, 162, 242, 288, 392, 512, 648, 722, 882, 968, 1058, 1152, 1458, 1568, 1922, 2048, 2178, 2592, 2888, 3528, 3698, 3872, 4232, 4418, 4608, 4802, 5832, 6272, 6498, 6962, 7688, 7938, 8192, 8712, 8978, 9522, 10082, 10368, 11552 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`Conjecture: for n>1 this is A050804.`
	FORMULA	`Conjecture: sequence consists of numbers of form 2k^2 such that sigma(2k^2)==3 (mod 4) and k is not divisible by 5.`
	CROSSREFS	`Cf. A050804.` `Sequence in context: A074629 A001105 A051787 this_sequence A050804 A018229 A166830` `Adjacent sequences: A081321 A081322 A081323 this_sequence A081325 A081326 A081327`
	KEYWORD	`nonn,new`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 20 2003`
	EXTENSIONS	`a(19)-a(45) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 15 2009`

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.

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