A121556 - OEIS

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A121556

Numbers such that sigma(n)^2 is divisible by UnitarySigma(n)*UnitaryPhi(n).

1, 2, 3, 6, 14, 15, 30, 35, 42, 70, 78, 105, 190, 210, 348, 357, 418, 570, 714, 910, 1045, 1144, 1254, 2090, 2296, 2730, 3135, 3432, 4060, 4522, 4674, 5278, 6270, 6888, 10168, 10659, 10824, 12180, 12441, 13566, 14630, 15834, 16770, 17160 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	MAPLE	`for n from 1 to 20000 do if numtheory[sigma](n)^2 mod (A047994(n)*A034448(n)) = 0 then printf("%d, ", n) ; end if; end do:`
	CROSSREFS	`Cf. A121647, A078557, A020492.` `Sequence in context: A134737 A030733 A122839 * A123041 A078557 A005537` `Adjacent sequences: A121553 A121554 A121555 * A121557 A121558 A121559`
	KEYWORD	`nonn`
	AUTHOR	`Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Sep 12 2006`

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.