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A030987 4-automorphic numbers: final digits of 4*n^2 agree with n. 1
4, 44, 344, 7344, 77344, 777344, 6777344, 46777344, 446777344, 446777344, 20446777344, 20446777344, 5020446777344, 35020446777344, 935020446777344, 5935020446777344, 35935020446777344 (list; graph; refs; listen; history; text; internal format)
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 xrange(1, 1001)] # Eric M. Schmidt, Aug 18 2012

CROSSREFS

Sequence in context: A220920 A035014 A259989 * A297384 A178294 A043039

Adjacent sequences:  A030984 A030985 A030986 * A030988 A030989 A030990

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein

STATUS

approved

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Last modified June 19 06:47 EDT 2019. Contains 324218 sequences. (Running on oeis4.)