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A062524
7^a(n) is smallest nonnegative power of 7 containing the string 'n'.
2
4, 0, 4, 3, 2, 7, 5, 1, 5, 2, 13, 6, 12, 12, 19, 15, 5, 6, 19, 11, 12, 22, 14, 7, 4, 30, 11, 23, 10, 16, 14, 19, 11, 16, 3, 7, 9, 19, 12, 17, 4, 12, 27, 3, 18, 21, 32, 10, 8, 2, 15, 17, 10, 9, 7, 21, 15, 8, 21, 18, 9, 15, 18, 17, 6, 27, 20, 11, 5, 16, 33, 27, 12, 11, 11, 10
OFFSET
0,1
COMMENTS
See A176767 for the actual powers 7^a(n). - M. F. Hasler, Oct 03 2014
MATHEMATICA
Table[k = 0; While[ StringPosition[ ToString[7^k], ToString[n] ] == {}, k++ ]; k, {n, 0, 75} ]
CROSSREFS
Cf. A030000.
Essentially the same as A063570.
Sequence in context: A361618 A367873 A016680 * A152856 A031362 A378012
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Jun 24 2001
STATUS
approved