a(n) = numerator of Sum_{i=1..n} +-1/n, where the sign is -1 iff n is prime.

Terms

a(0) =1a(1) =1a(2) =1a(3) =5a(4) =13a(5) =23a(6) =101a(7) =307a(8) =1201a(9) =1453a(10) =13463a(11) =15773a(12) =177329a(13) =203069a(14) =227093a(15) =499231a(16) =7766207a(17) =938543a(18) =16470957a(19) =17764249a(20) =56987867a(21) =60515027a(22) =1314248101a(23) =462870797a(24) =2433336849a(25) =2547743449a(26) =71763644723a(27) =74631981623