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A362229
a(n) is the largest m such that uphi(m) = n, where uphi is the unitary totient function (A047994), or a(n) = 0 if no such m exists.
3
2, 6, 4, 10, 0, 14, 8, 30, 0, 22, 0, 42, 0, 24, 16, 34, 0, 38, 0, 66, 0, 46, 0, 78, 0, 54, 0, 58, 0, 62, 32, 102, 0, 0, 0, 114, 0, 0, 0, 110, 0, 86, 0, 138, 0, 94, 0, 210, 0, 0, 0, 106, 0, 76, 0, 174, 0, 118, 0, 186, 0, 96, 64, 170, 0, 134, 0, 0, 0, 142, 0, 222
OFFSET
1,1
LINKS
FORMULA
a(A347771(n)) = 0.
EXAMPLE
a(1) = 2 since there are two solutions to uphi(x) = 1: 1 and 2, and 2 is the larger of them.
a(6) = 14 since there are three solutions to uphi(x) = 6: 7, 12 and 14, and 14 is the largest of them.
MATHEMATICA
a[n_] := If[(inv = invUPhi[n]) == {}, 0, Max[inv]]; Array[a, 100] (* using the function invUPhi from A361966 *)
CROSSREFS
The unitary version of A057635.
Cf. A047994, A347771 (positions of 0's), A361966, A362230 (record values), A362231 (indices of records).
Sequence in context: A201895 A192408 A074208 * A333775 A334205 A227389
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 12 2023
STATUS
approved