id:A067739 - OEIS Search Results

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Integers x such that for some integer y we have uphi(x)=uphi(y)=x-y, where uphi(n)=A047994(n) is the unitary totient function: If n = Product p_i^e_i, uphi(n) = Product (p_i^e_i - 1).

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2, 60, 390, 840, 2310, 2910, 4386, 6090, 10374, 11220, 13860, 21882, 33654, 51090, 82680, 114294, 140910, 157080, 159530, 168630, 203190, 272514, 282170, 318318, 332010, 362670, 367080, 393414, 403130, 411990, 434070, 492882, 499590, 585390 (list; graph; listen)

	OFFSET	`0,1`
	MATHEMATICA	`uphi[n_] := Times@@(Power@@#-1&/@FactorInteger[n]); For[x=1, True, x++, If[uphi[y=x-(u=uphi[x])]==u, Print[{x, y}]]]`
	CROSSREFS	`Cf. A047994, A067741.` `Sequence in context: A078511 A141055 A048541 this_sequence A059934 A006333 A001760` `Adjacent sequences: A067736 A067737 A067738 this_sequence A067740 A067741 A067742`
	KEYWORD	`nonn`
	AUTHOR	`Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)`
	EXTENSIONS	`Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Mar 07 2002`

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

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