a(n) is the Severi degree for curves of degree n and cogenus 3.

Terms

a(0) =0a(1) =0a(2) =15a(3) =675a(4) =7915a(5) =41310a(6) =145383a(7) =404185a(8) =959115a(9) =2029980a(10) =3939295a(11) =7139823a(12) =12245355a(13) =20064730a(14) =31639095a(15) =48282405a(16) =71625163a(17) =103661400a(18) =146798895a(19) =203912635a(20) =278401515a(21) =374248278a(22) =496082695a(23) =649247985a(24) =839870475a(25) =1074932500a(26) =1362348543a(27) =1711044615