a(n) = self-convolution of row n of array T given by A027113.

Terms

a(0) =1a(1) =5a(2) =18a(3) =76a(4) =311a(5) =1245a(6) =4882a(7) =18818a(8) =71529a(9) =268785a(10) =1000422a(11) =3693814a(12) =13545669a(13) =49382777a(14) =179117070a(15) =646786228a(16) =2326351527a(17) =8338190053a(18) =29792805066a(19) =106152792682a(20) =377267681865