A071906 Sum of digits of 2^n (mod 2).

1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1

Offset: 0

Author

Santi Spadaro, Jun 13 2002

Keywords

• base
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A001370.

Programs

Mathematica

f[n_] := Mod[Plus @@ IntegerDigits[2^n], 2]; Table[ f@n, {n, 0, 104}] (* Robert G. Wilson v, May 04 2009 *)

PARI

a(n) = sumdigits(2^n) % 2; \\ Michel Marcus, Apr 20 2017