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A030164 Numbers n such that uphi(sigma(n)) = n, where the uphi is the unitary phi function A047994. 2
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 (list; graph; refs; listen; history; text; internal format)
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
Sequence in context: A127330 A344342 A035346 * A066646 A215488 A110920
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified May 19 09:42 EDT 2024. Contains 372683 sequences. (Running on oeis4.)