a(n+3) = 2*a(n+2) + a(n+1) + a(n) with a(0)=0, a(1)=6, a(2)=8.

Terms

a(0) =0a(1) =6a(2) =8a(3) =22a(4) =58a(5) =146a(6) =372a(7) =948a(8) =2414a(9) =6148a(10) =15658a(11) =39878a(12) =101562a(13) =258660a(14) =658760a(15) =1677742a(16) =4272904a(17) =10882310a(18) =27715266a(19) =70585746a(20) =179769068a(21) =457839148a(22) =1166033110a(23) =2969674436a(24) =7563221130a(25) =19262149806a(26) =49057195178a(27) =124939761292a(28) =318198867568a(29) =810394691606