OFFSET
3,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 3..1000
A. J. Schwenk, Enumeration of Hamiltonian cycles in certain generalized Petersen graphs, J. Combin. Theory B 47 (1) (1989) 53-59.
Index entries for linear recurrences with constant coefficients, signature (0, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 0, 1).
FORMULA
G.f. -x^3*(3 +8*x -5*x^3 -4*x^4 +x^5 -5*x^6 +x^9 +2*x^10 +x^11 -3*x^2 -5*x^8) / ( (1+x) *(x^2-x+1) *(x^4+x^2-1) *(x-1)^2 *(1+x+x^2)^2 )
MAPLE
A195197 := proc(n)
if modp(n, 6) =0 or modp(n, 6) = 2 then
2*(combinat[fibonacci](n/2+2)-combinat[fibonacci](n/2-2)-1) ;
elif modp(n, 6) = 1 then
n;
elif modp(n, 6) = 3 then
3;
elif modp(n, 6) = 4 then
n+2*(combinat[fibonacci](n/2+2)-combinat[fibonacci](n/2-2)-1) ;
else
0;
end if;
end proc:
MATHEMATICA
CoefficientList[Series[-(3 + 8*x - 5*x^3 - 4*x^4 + x^5 - 5*x^6 + x^9 + 2*x^10 + x^11 - 3*x^2 - 5*x^8)/((1+x)*(x^2-x+1)*(x^4+x^2-1)*(x-1)^2*(1+x+x^2)^2), {x, 0, 60}], x] (* Vincenzo Librandi, Dec 23 2012 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Sep 11 2011
STATUS
approved