A137460 Prime numbers k such that k^2 +- (k+1) are primes.

3, 5, 17, 71, 101, 131, 677, 839, 857, 1091, 1217, 2129, 2309, 2339, 2957, 3137, 3449, 3989, 4409, 6569, 6719, 6761, 7229, 8501, 8627, 8807, 9521, 9689, 9749, 10589, 10631, 11621, 11777, 11927, 12641, 13487, 13931, 14519, 15527, 15797, 16007

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Apr 21 2008

Keywords

• nonn
• easy

Examples

			3^2 +- 4 -> (5,13) primes,
5^2 +- 6 -> (19,31) primes.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A053182, A091567.

Programs

Mathematica

Select[Prime[Range[800]], PrimeQ[ #^2 - (# + 1)] && PrimeQ[ #^2 + (# + 1)] &]

Formula

A053182 INTERSECT A091567. - R. J. Mathar, Apr 19 2009

Extensions

More terms from Karl Hovekamp, Jan 24 2009