A063553 - OEIS

%I #9 Jun 26 2018 05:03:14

%S 1,3,19,47,23,82,91,74,165,201,147,229,213,267,281,265,342,422,416,

%T 350,322,470,454,426,537,642,631,439,593,677,625,554,723,700,745,818,

%U 896,809,995,930,957,980,1031,1045,1121,1210,891,1191,1154,1369,1230

%N Smallest k such that 2^k has exactly n 8's in its decimal representation.

%t a = {}; Do[k = 1; While[ Count[ IntegerDigits[2^k], 8] != n, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

%o (PARI) a(n)={my(k=1); while(n<>#select(d->d==8, digits(2^k)), k++); k} \\ _Andrew Howroyd_, Jun 26 2018

%Y Cf. A063115, A063426, A063429, A063430, A063526, A063540, A063552, A063554.

%K base,nonn

%O 0,2

%A _Robert G. Wilson v_, Aug 10 2001

%E Name corrected by _Jon E. Schoenfield_, Jun 25 2018