Numerator of Sum_{k=1..n}(-1)^k/phi(k), where phi = A000010.

Terms

a(0) =-1a(1) =0a(2) =-1a(3) =0a(4) =-1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =5a(10) =19a(11) =17a(12) =29a(13) =13a(14) =21a(15) =13a(16) =47a(17) =181a(18) =503a(19) =593a(20) =533a(21) =121a(22) =1259a(23) =1457a(24) =6889a(25) =7549a(26) =7109a(27) =7769a(28) =52403a(29) =59333