a(n) = T(n,2), array T as in A049600.

Terms

a(0) =0a(1) =1a(2) =4a(3) =13a(4) =38a(5) =104a(6) =272a(7) =688a(8) =1696a(9) =4096a(10) =9728a(11) =22784a(12) =52736a(13) =120832a(14) =274432a(15) =618496a(16) =1384448a(17) =3080192a(18) =6815744a(19) =15007744a(20) =32899072a(21) =71827456a(22) =156237824a(23) =338690048a(24) =731906048a(25) =1577058304a(26) =3388997632a(27) =7264534528a(28) =15535702016