

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

This is to 7 as A176763 is to 3 and as A030001 is to 2.


LINKS

Table of n, a(n) for n=0..21.


FORMULA

a(n) = MIN{A000420(i) such that n in decimal representation is a substring of A000420(i)}.
a(n) = 7^A062524(n).  Michel Marcus, Sep 30 2014


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

Cf. A000420, A030001, A176763, A176764A176773.
Sequence in context: A235259 A321638 A005073 * A018865 A186488 A186487
Adjacent sequences: A176764 A176765 A176766 * A176768 A176769 A176770


KEYWORD

base,easy,nonn


AUTHOR

Jonathan Vos Post, Apr 25 2010


EXTENSIONS

More terms from Sean A. Irvine and Jon E. Schoenfield, May 05 2010
Extended to a(0) by M. F. Hasler, Oct 03 2014


STATUS

approved



