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

Author

Amarnath Murthy, Sep 01 2002

Keywords

• base
• nonn

Examples

			a(14) = 9 as 14 divides 98.
		

Links

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

Crossrefs

Cf. A075114, A075115, A075116, A075117.

Programs

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 *)

Extensions

Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003