A030992 7-automorphic numbers ending in 8: final digits of 7n^2 agree with n.

8, 68, 768, 2768, 72768, 872768, 3872768, 83872768, 683872768, 1683872768, 11683872768, 11683872768, 11683872768, 20011683872768, 820011683872768, 4820011683872768, 34820011683872768, 534820011683872768

Offset

1,1

Comments

a(n) is the unique positive integer less than 10^n such that a(n) is divisible by 2^n and 7a(n) - 1 is divisible by 5^n. - Eric M. Schmidt, Aug 18 2012

Links

Eric M. Schmidt, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Automorphic Number

Index entries for sequences related to automorphic numbers

Index entries for sequences related to final digits of numbers

Prog

(Sage) [crt(0, inverse_mod(7, 5^n), 2^n, 5^n) for n in range(1, 1001)] # Eric M. Schmidt, Aug 18 2012

Crossrefs

Sequence in context: A167859 A243246 A113357 * A091590 A303010 A087487

Adjacent sequences: A030989 A030990 A030991 * A030993 A030994 A030995

Keyword

nonn,base

Author

Eric W. Weisstein

Status

approved