A203444 - OEIS

A203444

Numbers in range of Dedekind Psi function: A001615.

1, 3, 4, 6, 8, 12, 14, 18, 20, 24, 30, 32, 36, 38, 42, 44, 48, 54, 56, 60, 62, 68, 72, 74, 80, 84, 90, 96, 98, 102, 104, 108, 110, 112, 114, 120, 126, 128, 132, 138, 140, 144, 150, 152, 158, 160, 162, 164, 168, 174, 176, 180, 182, 186, 192, 194, 198, 200

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OFFSET

1,2

COMMENTS

a(n) is even for n>2

LINKS

Enrique Pérez Herrero, Table of n, a(n) for n = 1..5000

Patrick Sole and Michel Planat, Extreme values of the Dedekind Psi function, J. Comb. Number Theory 3 (2011), no. 1, 33-38, arXiv:1011.1825v2.

MATHEMATICA

terms = 100; Clear[seq]; seq[k_] := seq[k] = Table[DirichletConvolve[j, MoebiusMu[j]^2, j, n], {n, 1, k terms}] // Union // PadRight[#, terms]&;

seq[k = 1]; seq[k++]; While[Print[k]; seq[k] != seq[k-1], k++];

seq[k] (* Jean-François Alcover, Dec 14 2018, after Jan Mangaldan in A001615 *)