Diagonal sums of the Riordan matrix A121576.

Terms

a(0) =1a(1) =2a(2) =7a(3) =29a(4) =139a(5) =731a(6) =4096a(7) =24005a(8) =145420a(9) =903503a(10) =5726290a(11) =36878978a(12) =240663403a(13) =1587928511a(14) =10575884599a(15) =71005972250a(16) =480071241463