a(n) = numerator(Sum_{k=1..n} d(k+1)/d(k)), where d is the number of divisors function.

Terms

a(0) =2a(1) =3a(2) =9a(3) =31a(4) =43a(5) =23a(6) =29a(7) =125a(8) =47a(9) =49a(10) =61a(11) =187a(12) =211a(13) =223a(14) =119a(15) =607a(16) =697a(17) =707a(18) =797a(19) =817a(20) =847a(21) =431a(22) =491a(23) =3973a(24) =4133a(25) =4253a(26) =4433a(27) =1491a(28) =1651a(29) =1661