Partial sums of A108019.

Terms

a(0) =0a(1) =4a(2) =40a(3) =332a(4) =2672a(5) =21396a(6) =171192a(7) =1369564a(8) =10956544a(9) =87652388a(10) =701219144a(11) =5609753196a(12) =44878025616a(13) =359024204980