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

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences computed from indices in prime factorization

Formula

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

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 *)

Prog

(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);

Crossrefs

Cf. A010872, A156552.

Cf. A329609 (gives positions of zeros).

Sequence in context: A176239 A361854 A292475 * A316716 A145462 A159934

Adjacent sequences: A329900 A329901 A329902 * A329904 A329905 A329906

Keyword

nonn

Author

Antti Karttunen, Dec 08 2019

Status

approved