Largest prime number p such that x^n + y^n mod p does not take all values on Z/pZ.

Terms

a(0) =7a(1) =29a(2) =61a(3) =223a(4) =127a(5) =761a(6) =307a(7) =911a(8) =617a(9) =1741a(10) =1171a(11) =2927a(12) =3181a(13) =2593a(14) =1667a(15) =4519a(16) =2927a(17) =10781a(18) =5167a(19) =6491a(20) =8419a(21) =7177a(22) =5501a(23) =7307a(24) =9829a(25) =11117a(26) =12703a(27) =20011a(28) =10789a(29) =13249