A075014 Smallest k such that the concatenation k, k-1 is divisible by n; or 0 if no such number exists.

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

Harvey P. Dale, Table of n, a(n) for n = 1..1000

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

Cf. A075114, A075115, A075116, A075117.

Sequence in context: A246185 A247469 A346872 * A304880 A086686 A361614

Adjacent sequences: A075011 A075012 A075013 * A075015 A075016 A075017

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