Indices of double-safe primes: p=prime(n) is double-safe: q=(p-1)/2 & r=(q-1)/2 are both prime (and q is safe).

A075133

Indices of double-safe primes: p=prime(n) is double-safe: q=(p-1)/2 & r=(q-1)/2 are both prime (and q is safe).

Terms

    a(0) =5a(1) =9a(2) =15a(3) =39a(4) =72a(5) =128a(6) =228a(7) =309a(8) =417a(9) =562a(10) =567a(11) =657a(12) =740a(13) =762a(14) =779a(15) =789a(16) =927a(17) =959a(18) =967a(19) =981a(20) =1214a(21) =1315a(22) =1364a(23) =1632a(24) =1650a(25) =1667a(26) =1785a(27) =1825a(28) =2295a(29) =2425

External references