Number of unitary divisors of central binomial coefficients.

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =4a(5) =4a(6) =4a(7) =8a(8) =8a(9) =8a(10) =16a(11) =16a(12) =16a(13) =16a(14) =16a(15) =32a(16) =32a(17) =32a(18) =32a(19) =32a(20) =64a(21) =64a(22) =64a(23) =64a(24) =64a(25) =64a(26) =64a(27) =64a(28) =128a(29) =128