id:A076215 - OEIS Search Results

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Square root of sum defined in A007475(n) and A001032(n).

+0
3

1, 5, 77, 92, 70, 195, 143, 3854, 357, 245, 413, 4088, 2257, 2222, 652, 679, 278949, 3366, 1281, 67963, 1612, 8555, 1518, 63412, 1159158, 2619, 2725, 13862, 60973, 3069, 10790, 3128, 4620, 5083, 42918, 3406 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`6a(n)^2 is divisible by A001032(n). Proof: Let s = A007475(n), n = A001032(n), then a(n)^2 = sum(k=s, s+n-1, k^2) = n/6*(2n^2+(6s-3)n+6s^2-6s+1).`
	EXAMPLE	`A001032(3)=11, A007475(3)=18, so 18^2+19^2+...+28^2 (11 terms) = 77^2.`
	CROSSREFS	`Cf. A001032, A007475.` `Sequence in context: A136300 A144997 A088756 this_sequence A059856 A001513 A028556` `Adjacent sequences: A076212 A076213 A076214 this_sequence A076216 A076217 A076218`
	KEYWORD	`nonn`
	AUTHOR	`Ralf Stephan (ralf(AT)ark.in-berlin.de), Nov 03 2002`

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Last modified December 6 22:55 EST 2009. Contains 170429 sequences.

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