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A176765
Smallest power of 5 whose decimal expansion contains n.
3
390625, 1, 25, 3125, 48828125, 5, 625, 78125, 78125, 390625, 6103515625, 11920928955078125, 125, 931322574615478515625, 244140625, 15625, 95367431640625, 30517578125, 2384185791015625, 1953125, 1220703125, 116415321826934814453125
OFFSET
0,1
COMMENTS
This is to 5 as A176763 is to 3 and as A030001 is to 2.
FORMULA
a(n) = MIN{A000351(i) such that n in decimal representation is a substring of A000351(i)}.
a(n) = 5^A062522(n). - Michel Marcus, Sep 30 2014
EXAMPLE
a(1) = 1 because 5^0 = 1 has "1" as a substring (not a proper substring, though).
a(2) = 25 because 5^2 = 25 has "2" as a substring.
a(3) = 3125 because 5^5 = 3125 has "3" as a substring.
MATHEMATICA
A176765[n_] := Block[{k = -1}, While[StringFreeQ[IntegerString[5^++k], IntegerString[n]]]; 5^k]; Array[A176765, 50, 0] (* Paolo Xausa, Apr 03 2024 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Apr 25 2010
EXTENSIONS
Corrected comment by Sean A. Irvine, May 05 2010
More terms from Sean A. Irvine and Jon E. Schoenfield, May 05 2010
a(0) prepended by Paolo Xausa, Apr 03 2024
STATUS
approved