a(n) = Sum_{k=0..2n} (k+1) * A025177(n, k).

Terms

a(0) =1a(1) =4a(2) =18a(3) =72a(4) =270a(5) =972a(6) =3402a(7) =11664a(8) =39366a(9) =131220a(10) =433026a(11) =1417176a(12) =4605822a(13) =14880348a(14) =47829690a(15) =153055008a(16) =487862838a(17) =1549681956a(18) =4907326194a(19) =15496819560a(20) =48814981614a(21) =153418513644a(22) =481176247338