Sum of upward diagonals of Eulerian triangle.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =13a(6) =38a(7) =125a(8) =449a(9) =1742a(10) =7269a(11) =32433a(12) =153850a(13) =772397a(14) =4088773a(15) =22746858a(16) =132601933a(17) =807880821a(18) =5132235182a(19) =33925263901a(20) =232905588441