A078622 Primes of the form prime(n)*prime(n*2)+2.

23, 67, 733, 1009, 4603, 16519, 66301, 154459, 161221, 173713, 327079, 750679, 1694809, 1940683, 2023741, 2042281, 3012169, 3852973, 4011523, 4704199, 5407561, 5536213, 7292251, 7347229, 8484901, 11359939, 11633971, 12559189

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Example

43 = prime(14), 107 = prime(14*2) and 43*107+2 = 4603 is prime, therefore 4603 is a term.

Mathematica

Select[Table[Prime[n]Prime[2n]+2, {n, 500}], PrimeQ] (* Harvey P. Dale, Nov 28 2011 *)

Prog

(PARI) for(n=1, 1000, p=prime(n); p2=prime(2*n); Q=p*p2+2; if(isprime(Q), print1(Q, ", ")))
(Magma) [ p: n in [1..400] | IsPrime(p) where p is NthPrime(n)*NthPrime(n*2)+2 ];

Crossrefs

Cf. A051779, A048880.

Sequence in context: A136064 A142302 A276262 * A280376 A134428 A195039

Adjacent sequences: A078619 A078620 A078621 * A078623 A078624 A078625

Keyword

nonn

Author

Reinhard Zumkeller, Dec 11 2002

Status

approved