A348198 Terms of A326835 having more divisors than any smaller term.

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

Author

Amiram Eldar, Oct 06 2021

Keywords

• nonn
• more

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, ...

Examples

			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.
		

Crossrefs

Cf. A326835, A328858, A348199.

Programs

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