a(n) is least N > 1 congruent to -1,0, or 1 mod i for all i=1,...,n.

Terms

a(0) =2a(1) =2a(2) =2a(3) =3a(4) =4a(5) =5a(6) =29a(7) =41a(8) =55a(9) =71a(10) =791a(11) =791a(12) =1079a(13) =1079a(14) =1079a(15) =30239a(16) =246960a(17) =246960a(18) =636481a(19) =636481a(20) =1360800a(21) =2162161a(22) =2162161a(23) =2162161a(24) =39412801a(25) =39412801a(26) =107881201a(27) =107881201a(28) =3625549201a(29) =3625549201