Row k = 1 of rectangular table A340940.

Terms

a(0) =1a(1) =1a(2) =2a(3) =9a(4) =46a(5) =253a(6) =1467a(7) =8842a(8) =54878a(9) =348489a(10) =2254007a(11) =14799922a(12) =98405915a(13) =661315560a(14) =4485060016a(15) =30660329139a(16) =211061833430