Column 2 of triangle A352093.

Terms

a(0) =1a(1) =8a(2) =46a(3) =256a(4) =1286a(5) =6400a(6) =30348a(7) =142352a(8) =652486a(9) =2958864a(10) =13238308a(11) =58745872a(12) =258345884a(13) =1128790784a(14) =4900778456a(15) =21168054432a(16) =90993848134a(17) =389548241904