%I
%S 2,3,5,7,17,19,29,31,37,41,97,127,131,211,223,227,229,233,239,241,439,
%T 443,449,457,461,463,727,733,739,743,751,757,761,769,773,863,877,881,
%U 883,887,967,971,977,983,991,997,1009,1013,1187,1193,1201,1901,1907,1913,1931,1933
%N Primes p such that denominator of Sum_{k=1..p1} 1/k^2} is a square.
%t a = {}; Do[If[Sqrt[Denominator[Sum[1/x^2, {x, 1, Prime[x]  1}]]] == Floor[Sqrt[Denominator[Sum[1/x^2, {x, 1, Prime[x]  1}]]]], AppendTo[a, Prime[x]]], {x, 1, 50}]; a
%Y Cf. A061002, A034602, A127029.
%K nonn
%O 1,1
%A _Artur Jasinski_, Jan 03 2007
%E More terms from _Franklin T. AdamsWatters_, Jan 21 2012
