A030164 Numbers n such that uphi(sigma(n)) = n, where the uphi is the unitary phi function A047994.

1, 2, 3, 6, 7, 8, 14, 24, 31, 56, 62, 127, 128, 248, 254, 384, 720, 896, 1016, 3968, 8191, 16256, 16382, 32768, 65528, 98304, 103680, 131071, 229376, 262142, 524287, 1015808, 1048448, 1048568, 1048574, 4161536, 4194296, 16777088, 29719872, 50181120

Offset

1,2

Comments

Fixed points of the function UnitaryPhi(sigma(n)) = 1, 2, 3, 6, 2, 6, 7, 8, 12, 8, 6, 18, 6, 14, 14, 30, 8, 24, 12,.. (Note that this list of numbers contains UnitaryPhi(sigma(n)), n>=1, not the fixed points a(n)).

Contains also 50181120 and 2147483648.

Links

Donovan Johnson, Table of n, a(n) for n = 1..51 (terms < 10^11)

Crossrefs

Cf. A047994, A030165.

Sequence in context: A127330 A344342 A035346 * A066646 A215488 A110920

Adjacent sequences: A030161 A030162 A030163 * A030165 A030166 A030167

Keyword

nonn

Author

Yasutoshi Kohmoto

Status

approved