Number of tieless quidditch games with n scoring events.

Terms

a(0) =2a(1) =4a(2) =4a(3) =8a(4) =12a(5) =24a(6) =40a(7) =80a(8) =140a(9) =280a(10) =504a(11) =1008a(12) =1848a(13) =3696a(14) =6864a(15) =13726a(16) =25740a(17) =51450a(18) =97240a(19) =194210a(20) =369512a(21) =737124a(22) =1410864a(23) =2810178a(24) =5408312a(25) =10752868a(26) =20801200a(27) =41273500a(28) =80233200a(29) =158851800