A075002 a(n) = smallest k such that A007908(k) is divisible by n.

1, 2, 2, 2, 5, 2, 11, 6, 8, 10, 106, 2, 11, 22, 5, 6, 21, 8, 27, 20, 11, 106, 33, 6, 25, 30, 26, 24, 31, 20, 46, 6, 113, 64, 45, 36, 21, 64, 11, 20, 3, 24, 19, 128, 35, 68, 8, 6, 53, 50, 21, 120, 83, 26, 135, 128, 27, 82, 104, 20

Offset

1,2

Comments

Conjecture: For every n, a(n) is well-defined.

The maximum of the first 10000 terms is a(6314) = 1002902 and A007908(1002902) is a 5902910-digit number. - Rick L. Shepherd, Oct 11 2015

Links

Rick L. Shepherd, Table of n, a(n) for n = 1..10000

Example

a(4) = 2 since A007908(2)=12 is divisible by 4.
a(7) = 11 as 7 divides A007908(11)=1234567891011 and 7 does not divide any smaller concatenations.

Prog

(PARI) a(n)=my(m=Mod(1, n), k=1); while(m, m=10^#Str(k++)*m+k); k \\ Charles R Greathouse IV, Oct 11 2015

Crossrefs

Cf. A007908.

Sequence in context: A029662 A077913 A069862 * A228917 A061311 A174960

Adjacent sequences: A074999 A075000 A075001 * A075003 A075004 A075005

Keyword

base,nonn

Author

Amarnath Murthy, Sep 01 2002

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003

Edited by Max Alekseyev, Sep 30 2015

Status

approved