Eigensequence of triangle A084938.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =6a(5) =23a(6) =105a(7) =550a(8) =3236a(9) =21127a(10) =152084a(11) =1204107a(12) =10484455a(13) =100487135a(14) =1060590050a(15) =12312607512a(16) =156705050156