id:A071562 - OEIS Search Results

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Numbers n such that the sum of the middle divisors of n (A071090) are not zero.

+0
4

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	OFFSET	`1,2`
	FORMULA	`Numbers of form m*k with m <= k <= 2m. - Vladeta Jovovic (vladeta(AT)eunet.rs), May 07 2005`
	MATHEMATICA	`f[n_] := Plus @@ Select[ Divisors[n], Sqrt[n/2] <= # < Sqrt[n*2] &]; Select[ Range[175], f[ # ] != 0 &]`
	CROSSREFS	`Cf. A071090, A071561.` `Also n such that A067742(n) is nonzero.` `Sequence in context: A143346 A138969 A161819 this_sequence A100345 A118363 A146982` `Adjacent sequences: A071559 A071560 A071561 this_sequence A071563 A071564 A071565`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), May 30 2002`

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

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