Exponential self-convolution of A232690.

Terms

a(0) =1a(1) =2a(2) =6a(3) =26a(4) =146a(5) =1014a(6) =8374a(7) =80282a(8) =875874a(9) =10719734a(10) =145422182a(11) =2166117018a(12) =35143677106a(13) =616926078326