Duplicate of A084057.

Terms

a(0) =1a(1) =6a(2) =16a(3) =56a(4) =176a(5) =576a(6) =1856a(7) =6016a(8) =19456a(9) =62976a(10) =203776a(11) =659456a(12) =2134016a(13) =6905856a(14) =22347776a(15) =72318976a(16) =234029056a(17) =757334016a(18) =2450784256a(19) =7930904576a(20) =25664946176a(21) =83053510656a(22) =268766806016a(23) =869747654656