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A348198
Terms of A326835 having more divisors than any smaller term.
3
1, 3, 9, 15, 45, 105, 225, 405, 495, 1155, 3675, 4455, 8085, 19635, 62475, 75735, 137445, 373065, 1187025, 1741905, 2611455, 8580495, 27301575, 50515245, 60063465, 248834355, 1021078905, 2374216515, 2822982855, 11695214685, 47990708535
OFFSET
1,2
COMMENTS
All the terms are odd since all the terms of A326835 are odd (as phi(1) = phi(2) = 1).
The corresponding numbers of divisors are 1, 2, 3, 4, 6, 8, 9, 10, 12, 16, 18, 20, 24, 32, 36, 40, 48, 64, 72, 80, 96, 128, 144, 160, 192, 256, 288, 320, 384, 512, 576, ...
EXAMPLE
The sequence A326835 begins with 1, 3, 5, 7, 9, 11, 13 and 15. The number of divisors of these terms are 1, 2, 2, 2, 3, 2, 2 and 4, respectively. The record values, 1, 2, 3 and 4, occur at 1, 3, 9 and 15, the first 4 terms of this sequence.
MATHEMATICA
q[n_] := Length @ Union[EulerPhi /@ (d = Divisors[n])] == Length[d]; dm = 0; s = {}; Do[If[q[n], d = DivisorSigma[0, n]; If[d > dm, dm = d; AppendTo[s, n]]], {n, 1, 10^6, 2}]; s
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Oct 06 2021
STATUS
approved