A062737 Primes p such that 4p-1 is also prime.

2, 3, 5, 11, 17, 41, 53, 71, 83, 131, 137, 173, 197, 227, 263, 281, 293, 383, 431, 467, 503, 521, 563, 587, 593, 617, 677, 683, 701, 743, 797, 827, 887, 911, 977, 983, 1013, 1061, 1091, 1151, 1163, 1181, 1277, 1307, 1361, 1481, 1511, 1523, 1553, 1607, 1613

Offset

1,1

Comments

For n>1, 4*a(n) is a solution to the equation phi(x-1) - phi(x) = x/2. - Farideh Firoozbakht, Dec 17 2014

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Maple

select(n -> isprime(n) and isprime(4*n-1), [2, seq(2*k+1, k=1..1000)]); # Robert Israel, Dec 17 2014

Prog

(PARI) { n=0; forprime (p=2, 10^5, if (isprime(4*p - 1), write("b062737.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 10 2009

Crossrefs

Cf. A005384, A007700, A005382.

Sequence in context: A014210 A203074 A014556 * A085613 A082605 A007755

Adjacent sequences: A062734 A062735 A062736 * A062738 A062739 A062740

Keyword

nonn,easy

Author

Reiner Martin, Jul 12 2001

Status

approved