a(n) is the smallest composite (pseudoprime) p such that Bell(n+p) == Bell(n)+Bell(n+1) (mod p).

Terms

a(0) =21361a(1) =8a(2) =4a(3) =134a(4) =6a(5) =4a(6) =57a(7) =6a(8) =34a(9) =65a(10) =14a(11) =9a(12) =14a(13) =6a(14) =4a(15) =21a(16) =12a(17) =4a(18) =26a(19) =8a(20) =26a(21) =779a(22) =102a(23) =99a(24) =33a(25) =8a(26) =4a(27) =14a(28) =12a(29) =4