Binomial transform of tau(n) (see A000005).

Terms

a(0) =1a(1) =3a(2) =7a(3) =16a(4) =35a(5) =75a(6) =159a(7) =334a(8) =696a(9) =1442a(10) =2976a(11) =6123a(12) =12562a(13) =25706a(14) =52492a(15) =107014a(16) =217877a(17) =443061a(18) =899957a(19) =1826078a(20) =3701783a(21) =7498261a(22) =15178255a(23) =30706320a(24) =62085915a(25) =125465715a(26) =253415981a(27) =511608490a(28) =1032427637a(29) =2082680887