Column 1 of triangle A379200; a(n) = A379200(n,1) for n >= 2.

Terms

a(0) =1a(1) =4a(2) =13a(3) =40a(4) =130a(5) =472a(6) =1863a(7) =7536a(8) =30144a(9) =118420a(10) =460746a(11) =1795688a(12) =7059729a(13) =28023636a(14) =111978480a(15) =448799712a(16) =1800225540a(17) =7223348112a(18) =29006342666a(19) =116643481440a(20) =469861180529