A102382 a(n) = A001221(A004094(n)).

0, 1, 1, 1, 1, 1, 2, 1, 2, 2, 1, 2, 2, 2, 2, 3, 2, 1, 4, 3, 4, 4, 4, 3, 1, 4, 4, 5, 2, 2, 2, 3, 3, 3, 2, 2, 3, 1, 2, 5, 4, 4, 3, 4, 4, 1, 4, 2, 4, 4, 3, 3, 3, 4, 2, 1, 3, 3, 4, 6, 5, 2, 4, 4, 4, 2, 3, 5, 5, 3, 1, 6, 4, 3, 4, 6, 3, 1, 4, 4, 4, 5, 4, 4, 3, 2, 2, 3, 3, 3, 6, 3, 4, 4, 3, 4, 4, 4, 3, 8, 3, 4, 5, 3, 4

Offset: 0

Author

Reinhard Zumkeller, Jan 06 2005

Keywords

• nonn
• base

Examples

			n = 19: reverse(2^19) = 882425 = 5^2*47*751, so a(19) = 3.
n = 38: reverse(2^38) = 449609778472 = 2^3*56201222309, so a(38) = 2. - _Sean A. Irvine_, Sep 26 2023
		

Crossrefs

Cf. A001221, A004094, A102383, A102384, A102385.

Programs

Mathematica

a[n_] := PrimeNu[IntegerReverse[2^n]]; Array[a, 100, 0] (* Amiram Eldar, Oct 02 2024 *)

PARI

a(n) = omega(fromdigits(Vecrev(digits(2^n)))); \\ Amiram Eldar, Oct 02 2024

Extensions

a(38) corrected by Sean A. Irvine, Sep 26 2023