A014390 Final 2 digits of 7^n.
1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7, 49, 43, 1, 7
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for sequences related to final digits of numbers
- Index entries for linear recurrences with constant coefficients, signature (1,-1,1).
Programs
-
Magma
[Modexp(7, n, 100): n in [0..110]]; // Vincenzo Librandi, Aug 16 2016
-
Mathematica
PowerMod[7,Range[0,70],100] (* Harvey P. Dale, Jan 23 2012 *) LinearRecurrence[{1,-1,1},{1,7,49},70] (* Harvey P. Dale, May 09 2018 *)
-
PARI
a(n)=lift(Mod(7,100)^n) \\ Charles R Greathouse IV, Jan 02 2013
-
Sage
[power_mod(7,n,50)for n in range(0,80)] # Zerinvary Lajos, Nov 27 2009
Formula
a(n) = 7^n mod 50. [Zerinvary Lajos, Nov 27 2009]