Smallest prime factor of Mersenne numbers 2^p-1, where p is prime.

Terms

a(0) =3a(1) =7a(2) =31a(3) =127a(4) =23a(5) =8191a(6) =131071a(7) =524287a(8) =47a(9) =233a(10) =2147483647a(11) =223a(12) =13367a(13) =431a(14) =2351a(15) =6361a(16) =179951a(18) =193707721a(19) =228479a(20) =439a(21) =2687a(22) =167a(24) =11447a(26) =2550183799