a(n) = 4*a(n-1) + 9*a(n-2), for n>1, with a(0)=1, a(1)=3.

A122120

a(n) = 4*a(n-1) + 9*a(n-2), for n>1, with a(0)=1, a(1)=3.

Terms

    a(0) =1a(1) =3a(2) =21a(3) =111a(4) =633a(5) =3531a(6) =19821a(7) =111063a(8) =622641a(9) =3490131a(10) =19564293a(11) =109668351a(12) =614752041a(13) =3446023323a(14) =19316861661a(15) =108281656551a(16) =606978381153

External references