OFFSET
1,1
LINKS
Jon E. Schoenfield, Table of n, a(n) for n = 1..80
Jon E. Schoenfield, Excel program
FORMULA
If A109405(n) has n digits, a(n) = A109405(n), otherwise a(n) = A109405(n) + 10^n. - Max Alekseyev, May 05 2007
EXAMPLE
2^14 = 16384 and 14 end with the same single digit 4, thus a(1) = 14.
MATHEMATICA
f[n_] := Block[{k = If[n == 1, 2, 10], m = 10^n}, While[ PowerMod[2, k, m] != Mod[k, m], k += 2]; k]; Do[ Print@f@n, {n, 9}] (* Robert G. Wilson v *)
PROG
(PARI) A121319(n) = { local(k, tn); tn=10^n ; forstep(k=2, 1000000000, 2, if ( k % tn == (2^k) % tn, return(k) ; ) ; ) ; return(0) ; } { for(n = 1, 13, print( A121319(n)) ; ) ; } \\ R. J. Mathar, Aug 27 2006
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Tanya Khovanova, Aug 25 2006
EXTENSIONS
a(6)-a(9) from Robert G. Wilson v and Jon E. Schoenfield, Aug 26 2006
a(10) from Robert G. Wilson v, Sep 26 2006
a(11)-a(16) from Alexander Adamchuk, Jan 28 2007
a(16) corrected by Max Alekseyev, Apr 12 2007
STATUS
approved