a(n) = 2*( a(n-5) + a(n-8) + a(n-11) ) for n >= 12.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =3a(7) =3a(8) =5a(9) =5a(10) =9a(11) =11a(12) =10a(13) =18a(14) =18a(15) =26a(16) =38a(17) =36a(18) =60a(19) =68a(20) =82a(21) =130a(22) =130a(23) =192a(24) =248a(25) =272a(26) =432a(27) =472a(28) =620a(29) =876