A070436 a(n) = n^2 mod 13.

0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4, 1, 0, 1, 4, 9, 3, 12, 10, 10, 12, 3, 9, 4

Offset: 0

Author

N. J. A. Sloane, May 12 2002

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,0,1).

Crossrefs

Cf. A070434, A070435.

Programs

Mathematica

Table[Mod[n^2,13],{n,0,200}] (* Vladimir Joseph Stephan Orlovsky, Apr 21 2011 *)

PARI

a(n)=n^2%13 \\ Charles R Greathouse IV, Apr 06 2016

Formula

G.f.: (x^12 +4*x^11 +9*x^10 +3*x^9 +12*x^8 +10*x^7 +10*x^6 +12*x^5 +3*x^4 +9*x^3 +4*x^2 +x)/(-x^13 +1). - Colin Barker, Aug 14 2012

a(n) = a(n-13). - G. C. Greubel, Mar 24 2016