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A361966
Irregular table read by rows in which the n-th row consists of all the numbers m such that uphi(m) = n, where uphi is the unitary totient function (A047994).
15
1, 2, 3, 6, 4, 5, 10, 7, 12, 14, 8, 9, 15, 18, 30, 11, 22, 13, 20, 21, 26, 42, 24, 16, 17, 34, 19, 28, 38, 33, 66, 23, 46, 25, 35, 36, 39, 50, 60, 70, 78, 27, 54, 29, 40, 58, 31, 44, 48, 62, 32, 45, 51, 90, 102, 37, 52, 57, 74, 84, 114, 41, 55, 82, 110, 43, 56, 86
OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..16006 (first 10000 rows)
EXAMPLE
The table begins:
n n-th row
-- --------
1 1, 2;
2 3, 6;
3 4;
4 5, 10;
5
6 7, 12, 14;
7 8;
8 9, 15, 18, 30;
9
10 11, 22;
11
12 13, 20, 21, 26, 42;
MATHEMATICA
invUPhi[n_] := Module[{fct = f[n], sol}, sol = Times @@@ (1 + Select[fct, UnsameQ @@ # && (Length[#] == 1 || CoprimeQ @@ (# + 1)) && Times @@ PrimeNu[# + 1] == 1 &]); Sort@ Join[sol, 2*Select[sol, OddQ]]]; invUPhi[1] = {1, 2}; Table[invUPhi[n], {n, 1, 50}] // Flatten (* using the function f by T. D. Noe at A162247 *)
CROSSREFS
The unitary version of A032447.
Sequence in context: A178484 A222758 A127915 * A358026 A331117 A282841
KEYWORD
nonn,tabf
AUTHOR
Amiram Eldar, Apr 01 2023
STATUS
approved