A329903 a(n) = A156552(n) mod 3.

0, 1, 2, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 2, 1, 0, 1, 1, 2, 1, 0, 0, 1, 2, 0, 2, 2, 2, 2, 0, 1, 1, 1, 0, 2, 0, 2, 2, 0, 0, 1, 1, 2, 1, 1, 0, 1, 2, 0, 1, 1, 2, 2, 2, 0, 2, 0, 2, 1, 1, 2, 0, 2, 0, 2, 0, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 1, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 1, 1, 0, 2, 2, 1, 1, 1, 0, 2, 0, 1, 2, 0

Offset: 1

Author

Antti Karttunen, Dec 08 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for sequences computed from indices in prime factorization

Crossrefs

Cf. A010872, A156552.

Cf. A329609 (gives positions of zeros).

Programs

Mathematica

Array[Mod[#, 3] &@ Floor@ Total@ Flatten@ MapIndexed[#1 2^(#2 - 1) &, Flatten[Table[2^(PrimePi@ #1 - 1), {#2}] & @@@ FactorInteger@ #]] &, 105] (* Michael De Vlieger, Dec 27 2019 *)

PARI

A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
A329903(n) = (A156552(n)%3);

Formula

a(n) = A010872(A156552(n)) = A156552(n) mod 3.