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A062521
4^a(n) is smallest nonnegative power of 4 containing the string 'n'.
2
5, 0, 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, 29, 9, 7, 3, 8, 23, 12, 14, 17, 23, 13, 12, 15, 15, 22
OFFSET
0,1
MATHEMATICA
Table[k = 0; While[ StringPosition[ ToString[4^k], ToString[n] ] == {}, k++ ]; k, {n, 0, 75} ]
CROSSREFS
Cf. A030000. Essentially the same as A063567.
Sequence in context: A200417 A309723 A198839 * A271951 A157700 A099645
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Jun 24 2001
STATUS
approved