Sum of the numbers of unitary divisors of the binomial coefficients C(n,k), k=0..n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =10a(5) =14a(6) =22a(7) =22a(8) =30a(9) =46a(10) =74a(11) =94a(12) =90a(13) =102a(14) =130a(15) =170a(16) =198a(17) =222a(18) =290a(19) =350a(20) =474a(21) =650a(22) =730a(23) =734a(24) =746a(25) =838a(26) =962a(27) =1214a(28) =2138a(29) =2582