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A067741 Integers y such that for some integer x 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). 4
1, 36, 294, 504, 1830, 2142, 3042, 4746, 7380, 7782, 8100, 15642, 22734, 38610, 47736, 77166, 103320, 107114, 112110, 134070, 153270, 189434, 189954, 234024, 239850, 243438, 275834, 287790, 296646, 305910, 314262, 345042, 361350, 410424 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

MATHEMATICA

uphi[n_] := Times@@(Power@@#-1&/@FactorInteger[n]); For[y=1, True, y++, If[uphi[x=y+(u=uphi[y])]==u, Print[{y, x}]]]

CROSSREFS

Cf. A047994, A067739.

Sequence in context: A014136 A091081 A017462 * A185096 A073972 A092643

Adjacent sequences:  A067738 A067739 A067740 * A067742 A067743 A067744

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 February 16 09:00 EST 2012. Contains 205904 sequences.