Primes p such that phi(p*(p-1)/2) is a triangular number (A000217).
A291340
Primes p such that phi(p*(p-1)/2) is a triangular number (A000217).
Terms
- a(0) =2a(1) =617a(2) =11243a(3) =72817a(4) =134213a(5) =1083601a(6) =1301617a(7) =669175321a(8) =2759347757a(9) =5023245823a(10) =10904836391a(11) =11230923643a(12) =12828977503a(13) =27741297781
External references
- oeis: A291340