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

Offset: 1

Author

Benoit Cloitre, Feb 22 2002

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A067481.

Programs

Mathematica

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

PARI

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

Extensions

Corrected by T. D. Noe, Nov 01 2006

Corrected by Harvey P. Dale, Dec 23 2012