Row lengths of the irregular triangle defined in A090905.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =6a(5) =12a(6) =20a(7) =40a(8) =80a(9) =160a(10) =308a(11) =628a(12) =1256a(13) =2488a(14) =5000a(15) =9940a(16) =19928a(17) =39864a(18) =79660a(19) =159380a(20) =318724a(21) =637496a(22) =1274980a(23) =2549924a(24) =5099884a(25) =10199748a(26) =20399528a(27) =40799020a(28) =81598052a(29) =163196124