Self-convolution forms A093635.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =23a(5) =92a(6) =368a(7) =1573a(8) =6687a(9) =29961a(10) =133258a(11) =612277a(12) =2801021a(13) =13118117a(14) =61169118a(15) =290680439a(16) =1374997022a(17) =6603579274a(18) =31604621290a(19) =153080685045a(20) =739012183165