Least k such that k*6^n-1 , k*6^n+1, and 2*k*6^n-1 are prime; that is, twin primes and a Sophie Germain prime.

A212481

Least k such that k*6^n-1 , k*6^n+1, and 2*k*6^n-1 are prime; that is, twin primes and a Sophie Germain prime.

Terms

    a(0) =1a(1) =5a(2) =2a(3) =282a(4) =47a(5) =315a(6) =1530a(7) =255a(8) =287a(9) =1577a(10) =4902a(11) =817a(12) =1600a(13) =700a(14) =1540a(15) =422a(16) =9070a(17) =3190a(18) =6860a(19) =6627a(20) =5115a(21) =12462a(22) =2077a(23) =10010a(24) =20515a(25) =13487a(26) =6787a(27) =2235a(28) =23167a(29) =17022

External references