|
| |
|
|
A356747
|
|
Numbers m that divide A306070(m) = Sum_{k=1..m} bphi(k), where bphi is the bi-unitary totient function (A116550).
|
|
1
|
|
|
|
1, 2, 141, 1035, 2388, 3973, 5157, 14160, 37023, 68861, 99889, 116106, 117939, 627400, 1561944, 1626983, 5901444, 10054091, 12260525, 32619981, 49775099
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
The corresponding quotients A306070(m)/m are 1, 1, 57, 418, ... (see the link for more values).
a(22) > 6.5*10^8, if it exists.
|
|
|
LINKS
|
Table of n, a(n) for n=1..21.
Amiram Eldar, Table of n, a(n), A306070(a(n))/a(n) for n = 1..21.
|
|
|
MATHEMATICA
|
phi[x_, n_] := DivisorSum[n, MoebiusMu[#]*Floor[x/#] &]; bphi[n_] := DivisorSum[n, (-1)^PrimeNu[#]*phi[n/#, #] &, CoprimeQ[#, n/#] &]; seq = {}; s = 0; Do[s = s + bphi[n]; If[Divisible[s, n], AppendTo[seq, n]], {n, 1, 10^6}]; seq
|
|
|
CROSSREFS
|
Cf. A116550, A306070.
Similar sequences: A048290, A306950.
Sequence in context: A221601 A334013 A115890 * A215187 A101827 A283097
Adjacent sequences: A356744 A356745 A356746 * A356748 A356749 A356750
|
|
|
KEYWORD
|
nonn,more
|
|
|
AUTHOR
|
Amiram Eldar, Aug 25 2022
|
|
|
STATUS
|
approved
|
| |
|
|
