OFFSET
0,2
COMMENTS
Period: (1, 5, 25, 14, 33, 17, 11, 18, 16, 6, 30, 2, 10, 13, 28, 29, 34, 22, 36, 32, 12, 23, 4, 20, 26, 19, 21, 31, 7, 35, 27, 24, 9, 8, 3, 15) of length 36. - Zak Seidov, Feb 08 2011
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1).
FORMULA
From R. J. Mathar, Apr 20 2010: (Start)
a(n) = a(n-1) - a(n-18) + a(n-19).
G.f.: ( -1-4*x-20*x^2+11*x^3-19*x^4+16*x^5+6*x^6-7*x^7 +2*x^8+10*x^9 -24*x^10+28*x^11-8*x^12-3*x^13-15*x^14-x^15-5*x^16+12*x^17-15*x^18 ) / ( (x-1)*(x^2+1)*(x^4-x^2+1)*(x^12-x^6+1) ). (End)
a(n) = 37 - a(n-18). - Zak Seidov, Feb 08 2011
a(n) = a(n-36). - G. C. Greubel, Mar 16 2016
MATHEMATICA
a[n_]:=PowerMod[5, n, 37]; Table[a[n], {n, 72}] (* Zak Seidov, Feb 08 2011 *)
PROG
(Sage) [power_mod(5, n, 37) for n in range(0, 76)] # Zerinvary Lajos, Nov 26 2009
(PARI) a(n)=lift(Mod(5, 37)^n) \\ M. F. Hasler, Feb 08 2011
(PARI) a(n)=5^(n%36)%37 \\ M. F. Hasler, Feb 08 2011
(Magma) [Modexp(5, n, 37): n in [0..100]]; // Vincenzo Librandi, Jun 29 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 12 2002
STATUS
approved