a(n) = 3*a(n-1) + 6*a(n-2) + a(n-3), with a(0) = 3, a(1) = 3, and a(2) = 21.

A214778

a(n) = 3*a(n-1) + 6*a(n-2) + a(n-3), with a(0) = 3, a(1) = 3, and a(2) = 21.

Terms

    a(0) =3a(1) =3a(2) =21a(3) =84a(4) =381a(5) =1668a(6) =7374a(7) =32511a(8) =143445a(9) =632775a(10) =2791506a(11) =12314613a(12) =54325650a(13) =239656134a(14) =1057236915a(15) =4663973199a(16) =20574997221a(17) =90766067772a(18) =400412159841

External references