A070512 a(n) = n^4 mod 7.

0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2, 4, 4, 2, 1, 0, 1, 2

Offset: 0

Author

N. J. A. Sloane, May 13 2002

Keywords

• nonn
• easy

Comments

Equivalently: n^(4*m + 4) mod 7. - G. C. Greubel, Apr 01 2016

Links

• Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 1).

Programs

Magma

[Modexp(n, 4, 7): n in [0..100]]; // Vincenzo Librandi, Apr 02 2016

Mathematica

PowerMod[Range[0, 100], 4, 7] (* G. C. Greubel, Apr 01 2016 *)

PARI

a(n)=n^4%7 \\ Charles R Greathouse IV, Apr 06 2016

Sage

[power_mod(n,4,7)for n in range(0, 101)] # Zerinvary Lajos, Oct 30 2009

Formula

From G. C. Greubel, Apr 01 2016: (Start)

a(n) = a(n-7).

G.f.: x*(1 +2*x +4*x^2 +2*x^4 + x^5)/(1 - x^7). (End)