Bilinear recursive sequence.

Terms

a(0) =0a(1) =3a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =3a(8) =9a(9) =27a(10) =81a(11) =729a(12) =0a(13) =59049a(14) =-531441a(15) =14348907a(16) =-387420489a(17) =10460353203a(18) =-564859072962a(24) =0