A094114 a(n) = -Sum_{i=1..n-1} (-1)^i*2^valuation(i,3).

0, 1, 0, 2, 1, 2, 0, 1, 0, 4, 3, 4, 2, 3, 2, 4, 3, 4, 0, 1, 0, 2, 1, 2, 0, 1, 0, 8, 7, 8, 6, 7, 6, 8, 7, 8, 4, 5, 4, 6, 5, 6, 4, 5, 4, 8, 7, 8, 6, 7, 6, 8, 7, 8, 0, 1, 0, 2, 1, 2, 0, 1, 0, 4, 3, 4, 2, 3, 2, 4, 3, 4, 0, 1, 0, 2, 1, 2, 0, 1, 0, 16, 15, 16, 14, 15, 14, 16, 15, 16, 12, 13, 12, 14, 13, 14, 12

Offset: 1

Author

Benoit Cloitre, May 03 2004

Keywords

• nonn

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..6561
• Robert Ferréol (MathCurve), Cantor's (ternary) set [in French]

Crossrefs

Cf. A007949, A093347.

Programs

Maple

a:= n-> -add((-1)^i*2^padic[ordp](i, 3), i=1..n-1):
seq(a(n), n=1..100);  # Alois P. Heinz, Jan 05 2021

Mathematica

a[n_] := Sum[(-1)^(i+1) * 2^IntegerExponent[i, 3], {i, 1, n-1}]; Array[a, 100] (* Amiram Eldar, Jun 17 2022 *)

PARI

a(n)=-sum(i=1,n-1,(-1)^i*2^valuation(i,3))