Indices of triple-safe primes: p=prime(n) is double-safe: q=(p-1)/2, r=(q-1)/2 and s=(r-1)/2 are all prime (and q is double-safe).
A075134
Indices of triple-safe primes: p=prime(n) is double-safe: q=(p-1)/2, r=(q-1)/2 and s=(r-1)/2 are all prime (and q is double-safe).
Terms
- a(0) =9a(1) =15a(2) =128a(3) =228a(4) =417a(5) =562a(6) =1214a(7) =1364a(8) =2425a(9) =3085a(10) =5281a(11) =8256a(12) =8926a(13) =9187a(14) =9332a(15) =12782a(16) =14497a(17) =14607a(18) =16227a(19) =18763a(20) =19601a(21) =21476a(22) =29911a(23) =36080a(24) =36218a(25) =37083a(26) =38660a(27) =40104a(28) =40863a(29) =42094
External references
- oeis: A075134