A030987 4-automorphic numbers: final digits of 4*n^2 agree with n.

4, 44, 344, 7344, 77344, 777344, 6777344, 46777344, 446777344, 446777344, 20446777344, 20446777344, 5020446777344, 35020446777344, 935020446777344, 5935020446777344, 35935020446777344

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 4*a(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

Index entries for sequences related to automorphic numbers

Index entries for sequences related to final digits of numbers

Eric Weisstein's World of Mathematics, Automorphic Number

Prog

(Sage) [crt(0, (-5^n + 1)/4, 2^n, 5^n) for n in range(1, 1001)] # Eric M. Schmidt, Aug 18 2012

Crossrefs

Sequence in context: A220920 A035014 A259989 * A341590 A297384 A178294

Adjacent sequences: A030984 A030985 A030986 * A030988 A030989 A030990

Keyword

nonn,base

Author

Eric W. Weisstein

Status

approved