A333104 Unitary quasiperfect cototient numbers: numbers k such that the sum of the iterated unitary cototient function of k is equal to k+1.

10, 22, 98, 118, 230, 266, 1452, 88894, 114214, 1274198, 51675986, 61177358, 82986118

Offset

1,1

Comments

a(14) > 10^9.

Links

Table of n, a(n) for n=1..13.

Example

10 is a term since A323410(10) = 6, A323410(6) = 4, A323410(4) = 1 and 6 + 4 + 1 = 11 = 10 + 1.

Mathematica

uphi[0] = 0; uphi[1] = 1; uphi[n_] := (Times @@ (Table[#[[1]]^#[[2]] - 1, {1}] & /@ FactorInteger[n]))[[1]]; ucot[n_] := n - uphi[n]; Select[Range[10^4], Plus @@ FixedPointList[ucot, #] == 2*# + 1 &]

Crossrefs

Cf. A082897, A286067, A323410, A330273, A333103.

Sequence in context: A255048 A354879 A349847 * A214959 A054095 A125618

Adjacent sequences: A333101 A333102 A333103 * A333105 A333106 A333107

Keyword

nonn,more

Author

Amiram Eldar, Mar 07 2020

Status

approved