Bisection of A002417.

Terms

a(0) =8a(1) =80a(2) =336a(3) =960a(4) =2200a(5) =4368a(6) =7840a(7) =13056a(8) =20520a(9) =30800a(10) =44528a(11) =62400a(12) =85176a(13) =113680a(14) =148800a(15) =191488a(16) =242760a(17) =303696a(18) =375440a(19) =459200a(20) =556248a(21) =667920a(22) =795616a(23) =940800a(24) =1105000a(25) =1289808a(26) =1496880a(27) =1727936a(28) =1984760a(29) =2269200