OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..144
Index entries for linear recurrences with constant coefficients, signature (10, -17).
FORMULA
a(n) = 10*a(n-1) - 17*a(n-2) for n > 1; a(0) = 1, a(1) = 17.
G.f.: (1+7*x)/(1-10*x+17*x^2).
a(n) = ((1+3*sqrt(2))*(5+2*sqrt(2))^n + (1-3*sqrt(2))*(5-2*sqrt(2))^n)/2.
PROG
(Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((1+3*r)*(5+2*r)^n+(1-3*r)*(5-2*r)^n)/2: n in [0..18] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Aug 20 2009
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Al Hakanson (hawkuu(AT)gmail.com), Aug 15 2009
EXTENSIONS
Edited and extended beyond a(5) by Klaus Brockhaus, Aug 20 2009
STATUS
approved