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
Harvey P. Dale, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = 3432*n - 6476 for n > 3; a(1)=1, a(2)=843, a(3)=3827.
From Colin Barker, Mar 18 2012: (Start)
a(n) = 2*a(n-1) - a(n-2) for n > 5.
G.f.: x*(1 + 841*x + 2142*x^2 + 441*x^3 + 7*x^4)/(1-x)^2. (End)
MATHEMATICA
Join[{1, 843, 3827}, LinearRecurrence[{2, -1}, {7252, 10684}, 40]] (* Harvey P. Dale, Nov 28 2014 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, Feb 09 2006
STATUS
approved