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A216156 Period of powers of 11 mod 10^n. 2
10, 50, 500, 5000, 50000, 500000, 5000000, 50000000, 500000000, 5000000000, 50000000000, 500000000000, 5000000000000, 50000000000000, 500000000000000, 5000000000000000, 50000000000000000, 500000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Essentially the same as A093143. - R. J. Mathar, Sep 06 2012
Also period of squares mod 10^n. - Mohammed Yaseen, Apr 18 2023
LINKS
FORMULA
a(n) = 5*10^(n-1), n >= 2.
EXAMPLE
a(2) = 50 because 11^50 = 11739085287969531650666649599035831993898213898723001 = 1 mod 1000.
MATHEMATICA
Join[{10}, NestList[10*# &, 50, 20]] (* Paolo Xausa, Feb 20 2024 *)
CROSSREFS
Sequence in context: A124872 A240534 A223161 * A072296 A143558 A106041
KEYWORD
nonn,base,easy
AUTHOR
V. Raman, Sep 02 2012
STATUS
approved

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Last modified July 23 19:18 EDT 2024. Contains 374553 sequences. (Running on oeis4.)