id:A083531 - OEIS Search Results

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First difference sequence of A002191. Differences between possible values for sum of divisors of n.

+0
5

2, 1, 2, 1, 1, 4, 1, 1, 1, 3, 2, 4, 4, 2, 1, 1, 4, 2, 1, 1, 2, 2, 4, 6, 2, 1, 3, 2, 1, 5, 4, 2, 4, 2, 4, 6, 1, 2, 3, 2, 4, 2, 4, 2, 2, 2, 6, 1, 3, 2, 1, 1, 4, 1, 5, 2, 4, 6, 2, 4, 2, 2, 2, 2, 4, 3, 3, 2, 4, 2, 1, 3, 6, 2, 1, 3, 2, 4, 6, 2, 4, 1, 5, 2, 4, 2, 4, 6, 2, 6, 4, 3, 1, 2, 2, 4, 2, 4, 2, 6, 2, 2, 2, 4, 6 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`8 and 12 are the 6th and 7th possible values for` `sigma[x],since are sum of divisors of x=7 and x=11` `respectively, while 9,10,11 are impossible ones` `so 12-8=4=a(6)=A002191[7]-A002191[6].`
	MATHEMATICA	`t=Table[DivisorSigma[1, w], {w, 1, 25000}]; u=Union[%]; Delete[u-RotateRight[u], 1]`
	CROSSREFS	`Cf. A002191, A007609, A007369, A083532-A083536.` `Sequence in context: A134303 A078997 A024680 this_sequence A003417 A158986 A079900` `Adjacent sequences: A083528 A083529 A083530 this_sequence A083532 A083533 A083534`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), May 20 2003`

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Last modified November 30 13:13 EST 2009. Contains 167758 sequences.

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