A064398 Numbers n such that p(n) + p(n+1) is a square and n is prime.

7, 61, 293, 919, 2693, 9857, 13763, 16033, 18367, 39419, 44789, 64433, 132511, 157307, 195407, 213289, 241513, 243589, 258331, 293989, 332573, 436673, 462067, 478637, 523777, 583367, 976933, 983557, 1329673, 1481099, 1582069, 1753963

Offset

1,1

Links

Table of n, a(n) for n=1..32.

Example

7 is in the sequence because the seventh and eighth primes are 17 and 19. Added together, they make 36 which is the square of 6.

Mathematica

p = q = 1; Do[ p = q; q = Prime[n + 1]; If[ PrimeQ[n] && IntegerQ[ Sqrt[p + q]], Print[n]], {n, 1, 10^7/4} ]

Prog

(PARI) for(n=1, 10^6, x=prime(n)+prime(n+1); if(issquare(x) && isprime(n), print(n)))

Crossrefs

Sequence in context: A100698 A141952 A289723 * A275878 A129079 A249556

Adjacent sequences: A064395 A064396 A064397 * A064399 A064400 A064401

Keyword

nonn

Author

Jason Earls, Sep 29 2001

Extensions

More terms from Robert G. Wilson v, Sep 30 2001

Status

approved