OFFSET
0,1
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,0,4,-4).
FORMULA
a(n) = (1/12)*(4+2^(n/2)*(12*(1+(-1)^n)-2*(-i)^n+18*sqrt(2)*(1-(-1)^n)+5*i*(-i)^n*sqrt(2)-i^(n+1)*(-2*i+5*sqrt(2)))), where i = sqrt(-1). - Stefano Spezia, Aug 19 2019
MATHEMATICA
LinearRecurrence[{1, 0, 0, 4, -4}, {2, 8, 5, 9, 7}, 40] (* or *)
CoefficientList[Series[(2 + 6*x + 3*x^2 +4*x^3 - 10*x^4)/(1 - x - 4*x^4 + 4*x^5), {x, 0, 40}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Georg Fischer, Aug 17 2019
STATUS
approved