Expansion of Sum_{n>=0} x^n * Sum_{k=0..n} C(n,k)^2 * x^(2*k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =10a(6) =18a(7) =35a(8) =73a(9) =151a(10) =306a(11) =623a(12) =1286a(13) =2668a(14) =5531a(15) =11477a(16) =23889a(17) =49852a(18) =104175a(19) =217936a(20) =456534a(21) =957609a(22) =2010839a(23) =4226417a(24) =8891022a(25) =18719637a(26) =39443860a(27) =83170162a(28) =175484915a(29) =370491775