

A063567


4^a(n) = smallest positive power of 4 having n in its decimal representation.


2



5, 2, 4, 7, 1, 4, 2, 10, 7, 6, 5, 20, 25, 35, 9, 29, 2, 17, 15, 11, 28, 9, 36, 29, 5, 4, 9, 19, 24, 16, 11, 37, 38, 43, 35, 14, 8, 15, 7, 21, 6, 11, 16, 11, 9, 14, 21, 18, 10, 16, 26, 20, 30, 8, 14, 8, 4, 10, 25, 22, 22
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..60.


MATHEMATICA

a = {}; Do[k = 1; While[ StringPosition[ ToString[4^k], ToString[n] ] == {}, k++ ]; a = Append[a, k], {n, 0, 50} ]; a
sp4[n_]:=Module[{k=1, idn=IntegerDigits[n]}, While[SequenceCount[ IntegerDigits[ 4^k], idn] == 0, k++]; k]; Array[sp4, 70, 0] (* The program uses the SequenceCount function from Mathematica version 10 *) (* Harvey P. Dale, Mar 12 2016 *)


CROSSREFS

Essentially the same as A062521.
Sequence in context: A267830 A163334 A029683 * A072223 A246312 A124907
Adjacent sequences: A063564 A063565 A063566 * A063568 A063569 A063570


KEYWORD

base,nonn


AUTHOR

Robert G. Wilson v, Aug 10 2001


STATUS

approved



