Expansion of Sum_{n>=0} x^n * Sum_{k=0..n} C(n,k)^2 * x^(4*k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =5a(7) =10a(8) =17a(9) =26a(10) =38a(11) =59a(12) =101a(13) =182a(14) =326a(15) =564a(16) =945a(17) =1566a(18) =2622a(19) =4476a(20) =7750a(21) =13455a(22) =23231a(23) =39837a(24) =68101a(25) =116611a(26) =200526a(27) =346137a(28) =598438a(29) =1034227