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A075014
Smallest k such that the concatenation k, k-1 is divisible by n; or 0 if no such number exists.
1
1, 1, 2, 3, 1, 5, 2, 3, 5, 1, 17, 17, 6, 9, 11, 3, 16, 5, 7, 21, 2, 17, 18, 29, 26, 17, 5, 33, 8, 11, 35, 3, 17, 33, 26, 41, 11, 7, 17, 21, 13, 47, 4, 17, 41, 41, 27, 29, 9, 51, 50, 17, 21, 5, 61, 61, 35, 27, 52, 41, 29, 35, 68, 45, 6
OFFSET
1,3
LINKS
EXAMPLE
a(14) = 9 as 14 divides 98.
MATHEMATICA
skc[n_]:=Module[{k=1}, While[Mod[FromDigits[Flatten[IntegerDigits/@{k, k-1}]], n] != 0, k++]; k]; Array[skc, 70] (* Harvey P. Dale, Mar 04 2023 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 01 2002
EXTENSIONS
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003
STATUS
approved