Partial sums of A007489.

Terms

a(0) =0a(1) =1a(2) =4a(3) =13a(4) =46a(5) =199a(6) =1072a(7) =6985a(8) =53218a(9) =462331a(10) =4500244a(11) =48454957a(12) =571411270a(13) =7321388383a(14) =101249656696