A074208 - OEIS

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A074208

Least k >1 such that n divides sigma(k)-k.

2, 6, 4, 9, 14, 6, 8, 10, 15, 14, 20, 24, 27, 22, 16, 12, 39, 24, 48, 34, 18, 20, 52, 90, 40, 46, 42, 28, 68, 78, 32, 56, 45, 62, 84, 24, 70, 48, 66, 44, 63, 30, 50, 82, 78, 52, 116, 90, 75, 40, 132, 96, 80, 42, 36, 106, 99, 68, 148, 120, 130, 118, 64, 56, 117, 54, 136, 112 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	FORMULA	`sum(k=1, n, a(k)) seems to be asymptotic to c*n^2 with probably 0.8 < c < 0.9`
	PROG	`(PARI) a(n)=if(n<0, 0, s=2; while((sigma(s)-s)%n>0, s++); s)`
	CROSSREFS	`Cf. A070982.` `Sequence in context: A097265 A201895 A192408 * A066043 A145019 A066678` `Adjacent sequences: A074205 A074206 A074207 * A074209 A074210 A074211`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 17 2002`

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Last modified February 16 16:51 EST 2012. Contains 205938 sequences.