Least number k > n such that k^2 divides n^k - 1.

Terms

a(0) =4a(1) =21a(2) =6a(3) =1555a(4) =8a(5) =889a(6) =10a(7) =111a(8) =12a(9) =253a(10) =14a(11) =2041a(12) =16a(13) =21a(14) =18a(16) =20a(18) =22a(19) =39a(20) =24a(21) =1081a(22) =26a(23) =55a(24) =28a(25) =171a(26) =30a(27) =279241a(28) =32a(29) =9641a(30) =34a(31) =1191