A066103 Smallest m such that A001221(A001159(m)) = n.

2, 3, 4, 16, 12, 60, 96, 294, 720, 1936, 3920, 9680, 33712, 83248, 303408, 1517040, 5207472, 26972352, 74469808, 255166128

Offset: 1

Author

Labos Elemer, Dec 04 2001

Keywords

• nonn
• more

Comments

a(18) > 18000000. - Vaclav Kotesovec, Sep 06 2019

Crossrefs

Cf. A001159, A001221, A066102.

Programs

Mathematica

Do[m = 1; While[PrimeNu[DivisorSigma[4, m]] != n, m++]; Print[m], {n, 1, 16}] (* Vaclav Kotesovec, Sep 05 2019 *)

PARI

{ for (n=1, 100, m=1; while (omega(sigma(m, 4)) != n, m++); write("b066103.txt", n, " ", m) ) } \\ Harry J. Smith, Nov 14 2009

Formula

a(n) = Min(x : A001221(A001159(x)) = n) = Min(x; A066102(x) = n).

Extensions

a(13) from Harry J. Smith, Nov 14 2009

a(14)-a(17) from Vaclav Kotesovec, Sep 06 2019

a(18)-a(20) from Amiram Eldar, Jul 04 2024