Least prime factor of (2n)! - n! + 1 (= A237580(n)).

Terms

a(0) =2a(1) =23a(2) =5a(3) =59a(4) =7a(5) =59a(6) =87178286161a(7) =29a(8) =11a(9) =443a(10) =13a(11) =587a(13) =3307a(14) =17a(15) =43a(16) =19a(17) =131a(18) =83a(19) =2791a(20) =23a(21) =113a(23) =659a(24) =761a(25) =6108689a(26) =29a(27) =233a(28) =31a(29) =67a(30) =181a(32) =1561016461