A330006 Numbers m such that psi(m) > psi(k) for all k < m, where psi is the Dedekind psi function (A001615).

1, 2, 3, 4, 6, 10, 12, 18, 24, 30, 42, 54, 60, 78, 84, 90, 114, 120, 150, 168, 180, 210, 270, 294, 300, 330, 390, 420, 510, 546, 570, 630, 750, 780, 840, 990, 1050, 1170, 1260, 1470, 1650, 1680, 1890, 2100, 2310, 2730, 3150, 3360, 3570, 3990, 4290, 4620, 5250

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..808 (terms below 10^11)

Formula

A001615(a(n)) = A210523(n).

Example

The first 6 values of the psi function are 1, 3, 4, 6, 6, 12. The record values, 1, 3, 4, 6, 12 are at positions 1, 2, 3, 4, 6.

Mathematica

psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/FactorInteger[n][[;; , 1]]); seq = {}; pmax = 0; Do[p = psi[n]; If[p > pmax, pmax = p; AppendTo[seq, n]], {n, 1, 10^5}]; seq

Crossrefs

Cf. A001615, A210523 (record values).

Sequence in context: A249685 A343731 A181312 * A288784 A322164 A237823

Adjacent sequences: A330003 A330004 A330005 * A330007 A330008 A330009

Keyword

nonn

Author

Amiram Eldar, Nov 26 2019

Status

approved