a(n) = numerator(Sum_{k=1..n} (-1)^(k+1)/(prime(k)-1)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =41a(5) =3a(6) =53a(7) =437a(8) =5167a(9) =34189a(10) =36037a(11) =3833a(12) =3987a(13) =11521a(14) =274223a(15) =3458639a(16) =103063291a(17) =100392623a(18) =34273501a(19) =33510453a(20) =308270747a(21) =302107667a(22) =12626774467a(23) =12402802537a(24) =25216220279a(25) =124110148411