a(n) = 4*a(n-1) - 7*a(n-2) + 6*a(n-3) - 3*a(n-4), starting with 0, 1, 2, 3.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =4a(6) =0a(7) =-13a(8) =-40a(9) =-81a(10) =-122a(11) =-122a(12) =0a(13) =365a(14) =1094a(15) =2187a(16) =3280a(17) =3280a(18) =0a(19) =-9841a(20) =-29524a(21) =-59049a(22) =-88574a(23) =-88574a(24) =0a(25) =265721a(26) =797162a(27) =1594323a(28) =2391484a(29) =2391484