Expansion of g.f. x^2/(1-2*x-49*x^2).

Terms

a(0) =0a(1) =1a(2) =2a(3) =53a(4) =204a(5) =3005a(6) =16006a(7) =179257a(8) =1142808a(9) =11069209a(10) =78136010a(11) =698663261a(12) =5225991012a(13) =44686481813a(14) =345446523214