a(n) = 12*a(n-2) - 25*a(n-4) with initial terms 1,1,7,12.

Terms

a(0) =1a(1) =1a(2) =7a(3) =12a(4) =59a(5) =119a(6) =533a(7) =1128a(8) =4921a(9) =10561a(10) =45727a(11) =98532a(12) =425699a(13) =918359a(14) =3965213a(15) =8557008a(16) =36940081a(17) =79725121a(18) =344150647a(19) =742776252a(20) =3206305739a(21) =6920186999a(22) =29871902693a(23) =64472837688a(24) =278305188841a(25) =600669377281