Generalized central coefficients for k=3.

Terms

a(0) =1a(1) =1a(2) =10a(3) =19a(4) =190a(5) =442a(6) =4420a(7) =11395a(8) =113950a(9) =312814a(10) =3128140a(11) =8960878a(12) =89608780a(13) =264735892a(14) =2647358920a(15) =8006545891a(16) =80065458910a(17) =246643289830