A072012 a(n) = A072010(A072010(n)).

1, 2, 1, 4, 5, 2, 7, 8, 1, 10, 1, 4, 7, 14, 5, 16, 17, 2, 19, 20, 7, 2, 5, 8, 25, 14, 1, 28, 29, 10, 31, 32, 1, 34, 35, 4, 15, 38, 7, 40, 41, 14, 43, 4, 5, 10, 7, 16, 49, 50, 17, 28, 63, 2, 5, 56, 19, 58, 17, 20, 5, 62, 7, 64, 35, 2, 105, 68, 5, 70, 21, 8, 49, 30

Offset: 1

Author

Reinhard Zumkeller, Jun 05 2002

Keywords

• nonn
• mult

Links

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

Crossrefs

Cf. A072010, A072013.

Programs

Mathematica

b[n_] := If[n == 1, 1, Product[{p, e} = pe; Which[
     Mod[p, 4] == 1, p + 2,
     Mod[p, 4] == 3, p - 2,
     True, 2]^e, {pe, FactorInteger[n]}]];
a[n_] := b[b[n]];
Array[a, 100] (* Jean-François Alcover, Nov 21 2021 *)