Self-convolution of array T given by A026670.

Terms

a(0) =1a(1) =2a(2) =11a(3) =34a(4) =173a(5) =586a(6) =2917a(7) =10262a(8) =50503a(9) =181334a(10) =885831a(11) =3221146a(12) =15652239a(13) =57405038a(14) =277822147a(15) =1025177314a(16) =4945846997a(17) =18333973274a(18) =88224662549a(19) =328195843910