A224495 Smallest k such that k*2*p(n)^2+1=q is prime 2*k*q^2+1=r 2*k*r^2+1=s, r and s are also prime.

9, 126, 29, 237, 420, 2, 186, 30, 2349, 896, 1266, 147, 741, 140, 3021, 924, 19571, 896, 791, 11495, 32, 7016, 3522, 5336, 932, 5480, 107, 1439, 1770, 209, 4239, 1716, 477, 1196, 1446, 900, 9176, 1920, 2375, 39, 2351, 590, 2724, 422, 3171, 179, 1751, 426, 65

Offset: 1

Author

Pierre CAMI, Apr 08 2013

Keywords

• nonn

Links

• Pierre CAMI, Table of n, a(n) for n = 1..5600

Crossrefs

Cf. A224489, A224490, A224492, A224492, A224493, A224494, A224496.

Programs

Mathematica

a[n_] := For[k = 1, True, k++, p = Prime[n]; If[PrimeQ[q = k*2*p^2 + 1] && PrimeQ[r = k*2*q^2 + 1] && PrimeQ[k*2*r^2 + 1], Return[k]]]; Table[ a[n] , {n, 1, 49}] (* Jean-François Alcover, Apr 12 2013 *)