A332042 Number of integers whose Dedekind psi function (A001615) values are n.

1, 0, 1, 1, 0, 2, 0, 1, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 5, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 4, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 6, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 9, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0

Offset

1,6

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

a(6) = 2 since there are 2 solutions to psi(x) = 6: 4 and 5.

Mathematica

psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); m = 100; v = Table[0, {m}]; Do[i = psi[k]; If[i <= m, v[[i]]++], {k, 1, m}]; v

Crossrefs

Cf. A001615, A054973, A063974, A332036, A332038, A332040.

Sequence in context: A124304 A165408 A186733 * A171368 A322353 A359785

Adjacent sequences: A332039 A332040 A332041 * A332043 A332044 A332045

Keyword

nonn

Author

Amiram Eldar, Feb 05 2020

Status

approved