OFFSET
1,2
COMMENTS
From Wolfdieter Lang, May 09 2014: (Start)
We consider only the digits after the decimal point, and leading zero digits are ignored. E.g., for 1/200 = .005 one checks 5, 50, 500, ..., for a factor 200, to find 5000/200 = 25, hence a(200) = 5000 = a(20)*10.
The a(n)/n sequence starts 1, 25, 1, 625, 4, 0, 2, 15625, 12345679, 1, 82644628099173553719, 0, 59171597633136094674556213, 51, 0, 390625, 346, 0, 277, 25, 226757369614512471655328798185941, 20661157, 189, 0, 16, ... (End)
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EXAMPLE
a(4) = 2500 because 1/4=0.25 but cannot be 25 or 250 because they are not divisible by 4.
a(6) = 0 because 1/6=0.1666... and no number made of a 1 and repeating 6's is divisible by 6 (all these numbers are congruent to 4 mod 6).
From Wolfdieter Lang, May 09 2014: (Start)
a(27) = 3703703703703703703703703703703703703703703703703703703703703703703703703,
a(27)/27 = 137174211248285322359396433470507544581618655692729766803840877914951989.
(End)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
J. Lowell, May 03 2014
EXTENSIONS
a(11)..a(25) from Wolfdieter Lang, May 09 2014
a(21) corrected by J. Lowell, May 09 2014
STATUS
approved