OFFSET
1,1
COMMENTS
Conjecture: a(n) exists for all n.
MATHEMATICA
a[n_] := For[j = 1, j < 10^7, j++, p = Prime[n]; If[PrimeQ[q = j*2*p^3 - 1] && PrimeQ[r = j*2*p*q^2 - 1] && PrimeQ[s = j*2*p*r^2 - 1] && PrimeQ[j*2*p*s^2 - 1], Return[j]]]; Table[Print[an = a[n]]; an, {n, 1, 24}] (* Jean-François Alcover, Apr 12 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Apr 12 2013
EXTENSIONS
More terms from Jean-François Alcover, Apr 12 2013
STATUS
approved