OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (4, 4, -4, -3).
FORMULA
G.f.: g(t)=(1+t^2+4t^3)/(1-4t-4t^2+4t^3+3t^4) a(n)=A080042(n)-(1+(-1)^n)/2
a(0)=1, a(1)=4, a(2)=21, a(3)=100, a(n)=4*a(n-1)+4*a(n-2)- 4*a(n-3)- 3*a(n-4). - Harvey P. Dale, Aug 11 2015
MATHEMATICA
CoefficientList[Series[(1+t^2+4t^3)/(1-4t-4t^2+4t^3+3t^4), {t, 0, 25}], t]
With[{c=2+Sqrt[7]}, Floor[c^Range[0, 30]]] (* or *) LinearRecurrence[{4, 4, -4, -3}, {1, 4, 21, 100}, 30]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Mario Catalani (mario.catalani(AT)unito.it), Jan 21 2003
STATUS
approved