A025700 - OEIS

%I #14 Jun 24 2023 21:45:42

%S 1,2,3,5,7,10,13,17,21,26,31,37,43,50,57,65,73,82,91,101,111,122,133,

%T 144,156,168,181,194,208,222,237,252,268,284,301,318,336,354,373,392,

%U 412,432,453,474,495,517,539,562,585,609,633,658,683,709,735,762,789,817,845,874

%N Index of 3^n within sequence of numbers of form 3^i * 10^j.

%C First term different from A033638 is a(24) = 144 != A033638(24) = 145.

%o (PARI) a(n) = vecsearch(setbinop((i,j)->3^i * 10^j, [0..n], [0..logint(10^n, 3)]), 3^n); \\ _Michel Marcus_, Jun 24 2023

%Y Cf. A000244, A011557.

%Y Cf. A033638.

%K nonn

%O 0,2

%A _David W. Wilson_

%E Offset 0 from _Michel Marcus_, Jun 24 2023