A265209 - OEIS

%I #14 Jan 20 2016 23:41:20

%S 1,2,1,1,2,2,1,2,1,1,0,1,2,2,1,0,1,1,1,2,0,2,1,0,0,1,1,1,2,0,0,2,2,2,

%T 1,1,0,1,2,2,1,2,2,1,0,2,1,2,1,2,1,2,1,2,0,1,1,0,2,0,2,0,1,0,2,2,1,1,

%U 1,1,0,2,1,1,1,1,2,2,2,2,1,1,2,2

%N Irregular triangle read by rows in which row n lists the base-3 digits of 2^n, n >= 0.

%C The length of row n is A020915(n) = 1 + A136409(n).

%e Triangle begins:

%e   1

%e   2

%e   1  1

%e   2  2

%e   1  2  1

%e   1  0  1  2

%e   2  1  0  1

%e   1  1  2  0  2

%e   1  0  0  1  1  1

%e   2  0  0  2  2  2

%e   1  1  0  1  2  2  1

%e   2  2  1  0  2  1  2

%e   1  2  1  2  1  2  0  1

%e   1  0  2  0  2  0  1  0  2

%e   2  1  1  1  1  0  2  1  1

%e   1  1  2  2  2  2  1  1  2  2

%t (* Replace Flatten with Grid to display the triangle: *)

%t Flatten[Table[IntegerDigits[2^n, 3], {n, 0, 15}]]

%o (PARI) for(n=0,15,for(k=1,#digits(2^n,3),print1(digits(2^n,3)[k],", "))) \\ _Derek Orr_, Dec 24 2015

%Y Cf. A000079 (powers of 2), A003137, A004642 (powers of 2 written in base 3).

%Y Cf. A265210 (base 3 digits of 2^n in reverse order).

%K nonn,tabf,base

%O 0,2

%A _L. Edson Jeffery_, Dec 04 2015