Even bisection of A283848.

Terms

a(0) =23a(1) =86a(2) =339a(3) =1332a(4) =5298a(5) =21066a(6) =83987a(7) =334966a(8) =1336988a(9) =5338206a(10) =21321234a(11) =85176636a(12) =340338398a(13) =1360073016a(14) =5435820051a(15) =21727481616a(16) =86853790498a(17) =347214198246