

A176767


Smallest power of 7 whose decimal expansion contains n.


1



2401, 1, 2401, 343, 49, 823543, 16807, 7, 16807, 49, 96889010407, 117649, 13841287201, 13841287201, 11398895185373143, 4747561509943, 16807, 117649, 11398895185373143, 1977326743, 13841287201, 3909821048582988049
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OFFSET

0,1


COMMENTS



LINKS



FORMULA

a(n) = MIN{A000420(i) such that n in decimal representation is a substring of A000420(i)}.


EXAMPLE

a(1) = 1 because 7^0 = 1 has "1" as a substring (not a proper substring, though).
a(2) = 2401 because 7^4 = 2401 has "2" as a substring.
a(3) = 343 because 7^3 = 343 has "3" as a substring.


CROSSREFS



KEYWORD

base,easy,nonn


AUTHOR



EXTENSIONS



STATUS

approved



