A054565 - OEIS

A054565

Numbers n such that 3 is the first digit of 3^n.

1, 18, 20, 22, 41, 43, 62, 64, 66, 83, 85, 87, 106, 108, 110, 127, 129, 131, 150, 152, 171, 173, 175, 194, 196, 215, 217, 219, 236, 238, 240, 259, 261, 263, 280, 282, 284, 303, 305, 324, 326, 328, 347, 349, 368, 370, 372, 389, 391, 393, 412, 414, 416, 433

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[500], First[IntegerDigits[3^#]]==3&] (* Harvey P. Dale, Dec 23 2012 *)

PROG

(PARI) for(n=1, 100, if(floor(3^n/10^(floor(n*log(3)/log(10))))==3, print1(n, ", ")))

CROSSREFS

Cf. A067481.

Sequence in context: A027887 A088383 A067496 * A295745 A328934 A255848