Fifth column (k=4) of triangle A084938.

Terms

a(0) =1a(1) =4a(2) =14a(3) =52a(4) =217a(5) =1040a(6) =5768a(7) =36992a(8) =272584a(9) =2285184a(10) =21550656a(11) =226071744a(12) =2611146384a(13) =32911082496a(14) =449243785728