OFFSET
1,2
COMMENTS
More generally for any n>=floor((m+1)/2) the trace of M(n)^(-m) = binomial(2*m,m)*n-2^(2*m-1)+binomial(2*m-1,m).
LINKS
S. Barbero, Dickson Polynomials, Chebyshev Polynomials, and Some Conjectures of Jeffery, Journal of Integer Sequences, 17 (2014), #14.3.8.
FORMULA
a(1)=1 then a(n)=20n-22.
(Conjecture) G.f.: F(x)=(1+16*x+3*x^2)/(1-x)^2. - L. Edson Jeffery, Jan 21 2012
(Conjecture) a(n)=2*a(n-1)-a(n-2), n>1, a(0)=1, a(1)=18. - L. Edson Jeffery, Jan 21 2012
PROG
(PARI) a(n)=if(n<2, 1, 20*n-22)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 09 2006
STATUS
approved