A063571 Smallest power of 8 having n in its decimal representation.

4, 3, 3, 5, 2, 3, 2, 5, 1, 4, 10, 14, 3, 9, 6, 7, 8, 9, 10, 12, 7, 6, 17, 21, 10, 17, 6, 5, 9, 20, 26, 25, 5, 21, 9, 15, 12, 10, 13, 14, 4, 10, 9, 14, 6, 11, 14, 12, 17, 13, 18, 3, 7, 29, 13, 13, 16, 25, 11, 11, 20

Offset: 0

Author

Robert G. Wilson v, Aug 10 2001

Keywords

• base
• nonn

Comments

Variant of A062525 allowing only exponents larger than zero. [From R. J. Mathar, Dec 15 2008]

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000

Programs

Mathematica

a = {}; Do[k = 1; While[ StringPosition[ ToString[8^k], ToString[n] ] == {}, k++ ]; a = Append[a, k], {n, 0, 60} ]; a
sp8[n_]:=Module[{k=1},While[SequenceCount[IntegerDigits[ 8^k], IntegerDigits[ n]]<1,k++];k]; Array[sp8,70,0] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 07 2017 *)

Python

def a(n):
  k, pow8, s = 1, 8, str(n)
  while s not in str(pow8): k += 1; pow8 *= 8
  return k
print([a(n) for n in range(61)]) # Michael S. Branicky, Apr 03 2021