OFFSET
1,1
COMMENTS
lim_{n -> infinity} a(n)/a(n-1) = 3+2*sqrt(2).
LINKS
FORMULA
a(n) = ((50+31*sqrt(2))*(3-2*sqrt(2))^n+(50-31*sqrt(2))*(3+2*sqrt(2))^n)/4.
G.f.: x*(13-25*x)/(1-6*x+x^2).
PROG
(PARI) {m=20; v=concat([13, 53], vector(m-2)); for(n=3, m, v[n]=6*v[n-1]-v[n-2]); v}
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Feb 09 2009
EXTENSIONS
Replaced abbreviation by sqrt(2) Klaus Brockhaus, Feb 12 2009
G.f. corrected by Klaus Brockhaus, Sep 23 2009
STATUS
approved