a(n)= 5*a(n-1) +3*a(n-2) -15*a(n-3) +5*a(n-4) +3*a(n-5) -a(n-6).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =12a(6) =42a(7) =191a(8) =933a(9) =4680a(10) =23575a(11) =118989a(12) =600666a(13) =3032680a(14) =15311545a(15) =77306765a(16) =390314982a(17) =1970668439a(18) =9949740765a(19) =50235420192a(20) =253634480330