OFFSET
0,3
COMMENTS
Also binomial transform of Pell(n)(1-(-1)^n)/2.
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,0,-8,4).
FORMULA
G.f.: x(1-2x)/((1-2x^2)(1-4x+2x^2));
a(n)=(sqrt(2)/8)((2+sqrt(2))^n-(2-sqrt(2))^n+(sqrt(2))^n-(-sqrt(2))^n).
MATHEMATICA
LinearRecurrence[{4, 0, -8, 4}, {0, 1, 2, 8}, 30] (* Harvey P. Dale, Jan 01 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2004
STATUS
approved