id:A072277 - OEIS Search Results

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Smallest integer > 1 which is both n-gonal and centered n-gonal.

+0
1

10, 25, 51, 91, 148, 225, 325, 451, 606, 793, 1015, 1275, 1576, 1921, 2313, 2755, 3250, 3801, 4411, 5083, 5820, 6625, 7501, 8451, 9478, 10585, 11775, 13051, 14416, 15873, 17425, 19075, 20826, 22681, 24643, 26715, 28900, 31201, 33621, 36163 (list; graph; listen)

	OFFSET	`3,1`
	FORMULA	`a(n) = (n^3-n^2+2)/2`
	EXAMPLE	`a(4) = 25 is both square and centered square.`
	CROSSREFS	`Sequence in context: A024838 A020179 A022670 this_sequence A063424 A137930 A071289` `Adjacent sequences: A072274 A072275 A072276 this_sequence A072278 A072279 A072280`
	KEYWORD	`easy,nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net), Jul 09 2002`

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Last modified July 6 17:22 EDT 2008. Contains 140988 sequences.

AT&T Labs Research