0,9

a(n) = A077267(A000079(n));

a(A104321(n))=n and a(m)<>n for m < A104321(n);

N. J. A. Sloane conjectures a(n)>0 for n>15, see A102483.

Table of n, a(n) for n=0..87.

n=13: 2^13=8192 -> '102020102', a(13) = 4.

Table[DigitCount[2^n, 3, 0], {n, 0, 90}] (* Harvey P. Dale, May 06 2014 *)

Cf. A004642, A007089.

Sequence in context: A140751 A259922 A162741 * A242618 A180264 A225200

Adjacent sequences: A104317 A104318 A104319 * A104321 A104322 A104323

nonn

Reinhard Zumkeller, Mar 01 2005

approved