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A127042 Primes p such that denominator of Sum_{k=1..p-1} 1/k^2} is a square. 12

%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..p-1} 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. Adams-Watters_, Jan 21 2012

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Last modified February 22 23:44 EST 2020. Contains 332157 sequences. (Running on oeis4.)