Antidiagonal sums of the convolution array A213756.

Terms

a(0) =1a(1) =9a(2) =40a(3) =130a(4) =355a(5) =871a(6) =1994a(7) =4360a(8) =9245a(9) =19205a(10) =39356a(11) =79934a(12) =161415a(13) =324755a(14) =651870a(15) =1306596a(16) =2616609a(17) =5237265a(18) =10479280a(19) =20964090a(20) =41934571a(21) =83876479a(22) =167761330a(23) =335532160a(24) =671075045a(25) =1342162141a(26) =2684337764a(27) =5368690550