a(n) = Sum_{i = 1..n} 2^(n - i) * A000002(i).

Terms

a(0) =0a(1) =1a(2) =4a(3) =10a(4) =21a(5) =43a(6) =88a(7) =177a(8) =356a(9) =714a(10) =1429a(11) =2860a(12) =5722a(13) =11445a(14) =22891a(15) =45784a(16) =91569a(17) =183139a(18) =366280a(19) =732562a(20) =1465125a(21) =2930252a(22) =5860505a(23) =11721011a(24) =23442024a(25) =46884049a(26) =93768100a(27) =187536202a(28) =375072405a(29) =750144811