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).

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

Offset

1,2

Links

Donovan Johnson, Table of n, a(n) for n = 1..300

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: A017462 A226836 A218647 * A374503 A185096 A073972

Adjacent sequences: A067738 A067739 A067740 * A067742 A067743 A067744

Keyword

nonn

Author

Yasutoshi Kohmoto

Extensions

Edited by Dean Hickerson, Mar 07 2002

Offset corrected by Donovan Johnson, May 04 2013

Status

approved