|
|
A348002
|
|
Numbers with a record number of distinct values of the unitary totient function applied to their unitary divisors (A348001).
|
|
2
|
|
|
1, 3, 12, 60, 420, 660, 4620, 8580, 9240, 60060, 78540, 106260, 157080, 1021020, 1381380, 1492260, 1806420, 2762760, 2984520, 23483460, 34321980, 38798760, 46966920, 68643960, 681020340, 892371480, 1848483780, 1990674840, 2127962760, 3226266120
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
The corresponding record values are 1, 2, 4, 8, 13, 16, 26, 28, 32, 40, 50, 52, 64, 72, 80, 84, 100, 104, 128, 144, 168, 176, 200, 256, 288, 352, 360, 416, 424, 512, ...
This sequence is infinite since A348001 is unbounded: A348001(n) >= omega(n).
a(31) > 2*10^10.
|
|
LINKS
|
|
|
EXAMPLE
|
The first 12 terms of A348001(k) are 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2 and 4. The record values, 1, 2 and 4, are obtained at k = 1, 3 and 12. Therefore, this sequence begins with 1, 3, 12.
|
|
MATHEMATICA
|
f[p_, e_] := p^e - 1; uphi[1] = 1; uphi[n_] := Times @@ f @@@ FactorInteger[n]; s[n_] := Length @ Union[uphi /@ Select[Divisors[n], CoprimeQ[#, n/#] &]]; sm = 0; seq = {}; Do[s1 = s[n]; If[s1 > sm, sm = s1; AppendTo[seq, n]], {n, 1, 10^5}]; seq
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|