Numerator of Laguerre(n, -3).

Terms

a(0) =1a(1) =4a(2) =23a(3) =28a(4) =491a(5) =1249a(6) =19223a(7) =15476a(8) =3515161a(9) =1512661a(10) =14496817a(11) =228800107a(12) =11770539419a(13) =60428965661