A307004 -id:A307004 - cp's OEIS frontend

A377711 Numbers that have a record number of (1+phi)-divisors (A061389).

1, 2, 6, 24, 30, 96, 120, 210, 480, 840, 1920, 2310, 3360, 9240, 13440, 30030, 36960, 120120, 147840, 332640, 480480, 1330560, 1921920, 4324320, 8168160, 17297280, 30750720, 32672640, 73513440, 155195040, 294053760, 522762240, 620780160, 1396755360, 2646483840

Offset: 1

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Amiram Eldar, Nov 04 2024

nonn

Indices of records in A061389.

The corresponding record values are 1, 2, 4, 6, 8, 10, 12, 16, 20, 24, 28, 32, 40, 48, 56, ... (see the link for more values).

Amiram Eldar, Table of n, a(n) for n = 1..231
Amiram Eldar, Table of n, a(n), A363825(a(n)) for n = 1..231

Cf. A061389, A307004.

Subsequence of A025487.

f[p_, e_] := EulerPhi[e] + 1; d[1] = 1; d[n_] := Times @@ f @@@ FactorInteger[n]; v = Cases[Import["https://oeis.org/A025487/b025487.txt", "Table"], {, }][[;; , 2]]; seq = {}; dm = 0; Do[If[(dk = d[v[[k]]]) > dm, dm = dk; AppendTo[seq, v[[k]]]], {k, 1, Length[v]}]; seq

cp's OEIS Frontend

A377711 Numbers that have a record number of (1+phi)-divisors (A061389).

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