A062291 Primes p = prime(k) such that k*p - 1 is also a prime.

3, 19, 37, 43, 61, 113, 251, 317, 359, 409, 463, 491, 557, 601, 683, 827, 863, 941, 1061, 1097, 1109, 1213, 1283, 1291, 1399, 1423, 1481, 1583, 1657, 1693, 1699, 1811, 2069, 2267, 2297, 2531, 2687, 2741, 2851, 3011, 3181, 3271, 3323, 3331, 3347, 3373

Offset

1,1

Links

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

Example

19 is in the sequence because 19 is the 8th prime and 8*19 - 1 = 151 is a prime.

Mathematica

Select[ Prime[ Range[ 500 ] ], PrimeQ[ # PrimePi[ # ]-1 ]& ]

Prog

(PARI) for(n=1, 200, if(isprime(n*prime(n)-1), print(prime(n))))
(PARI) { n=k=0; forprime (p=2, 5*10^5, k++; if (isprime(k*p - 1), write("b062291.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 04 2009

Crossrefs

Sequence in context: A069516 A098856 A178201 * A106082 A283714 A187828

Adjacent sequences: A062288 A062289 A062290 * A062292 A062293 A062294

Keyword

easy,nonn

Author

Jason Earls, Jul 02 2001

Extensions

More terms from Harvey P. Dale, Jul 05 2001

Status

approved