Third extended Jacobsthal recurrence: a(n)=4a(n-1)-6(n-2)+4a(n-3)-a(n-4)+2a(n-5).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =4a(6) =10a(7) =20a(8) =35a(9) =58a(10) =100a(11) =192a(12) =405a(13) =880a(14) =1874a(15) =3844a(16) =7631a(17) =14886a(18) =29020a(19) =57192a(20) =114249a(21) =230300a(22) =465226a(23) =936948a(24) =1877771a(25) =3748498a(26) =7470532a(27) =14895728a(28) =29749837a(29) =59514152