The Lambda triangle.

Terms

a(0) =1a(1) =-107a(2) =10a(3) =59845a(4) =-7497a(5) =210a(6) =-6059823a(7) =854396a(8) =-35574a(9) =420a(10) =5508149745a(11) =-827924889a(12) =41094790a(13) =-765534a(14) =4620a(17) =-75405128227a(18) =1738417252a(19) =-17219202a(20) =60060