a(n) = a(n-1) - (n-4)*a(n-4), with a(0)=0, a(1)=1, a(2)=2, a(3)=1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =1a(4) =1a(5) =0a(6) =-4a(7) =-7a(8) =-11a(9) =-11a(10) =13a(11) =62a(12) =150a(13) =249a(14) =119a(15) =-563a(16) =-2363a(17) =-5600a(18) =-7266a(19) =1179a(20) =38987a(21) =134187a(22) =264975a(23) =242574a(24) =-537166a(25) =-3355093a(26) =-9184543a(27) =-14763745a(28) =-1871761a(29) =82005564