A Jacobsthal-Lucas convolution.

Terms

a(0) =0a(1) =0a(2) =2a(3) =3a(4) =12a(5) =25a(6) =66a(7) =147a(8) =344a(9) =765a(10) =1710a(11) =3751a(12) =8196a(13) =17745a(14) =38234a(15) =81915a(16) =174768a(17) =371365a(18) =786438a(19) =1660239a(20) =3495260a(21) =7340025a(22) =15379122a(23) =32156323a(24) =67108872a(25) =139810125a(26) =290805086a(27) =603979767a(28) =1252698804a(29) =2594876065