[seqfan] Squares of the form x^2+40y^2 .
zak seidov
zakseidov at yahoo.com
Thu Jan 22 22:31:07 CET 2009
Dear seqfans,
Is this sequence finite?
%I A000001
%S A000001 1001,1463,1729,1771,2002,2093,2717,2849,2926,3003,3059,3157
%N A000001 Numbers n with property that n^2 has exactly 13 representations as x^2+40y^2 with positive x, y.
%C A000001 Is the sequence finite?
%e A000001 n=1001: {x,y}={{169,156},{231,154},{279,152},{371,147},{429,143},{681,116},{749,105},{781,99},{819,91},{871,78},{921,62},{979,33},{999,10}};
%e A000001 n=1463: {x,y}={{77,231},{247,228},{627,209},{653,207},{777,196},{787,195},{903,182},{1197,133},{1273,114},{1287,110},{1353,88},{1427,51},{1453,27}}.
%Y A000001 A107145 Primes of the form x^2+40y^2.
%K A000001 nonn
%O A000001 1,1
%A A000001 Zak Seidov (zakseidov(AT)yahoo.com), Jan 22 2009
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