%I A101931
%S A101931 1,16,158,1593,15919,159139,1591579,15915492,159154994
%N A101931 Number of primitive Pythagorean triples with hypotenuse < 10^n.
%C A101931 The ratio a(n)/10^n as n->inf is 1/(2*pi) = 0.15915... (Lehmer). - Tito 
               Piezas III (tpiezas(AT)gmail.com), Aug 11 2006
%D A101931 D. N. Lehmer, Asymptotic Evaluation of Certain Totient Sums, Amer. J. 
               Math. 22, 293-335, 1900.
%H A101931 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               PythagoreanTriple.html">Pythagorean Triple</a>
%e A101931 a(1)=1 because there is one primitive solution (a,b,c) as (3,4,5) with 
               c<10^1.
%Y A101931 Cf. A101929, A101930.
%Y A101931 Sequence in context: A144499 A155649 A036973 this_sequence A041005 A144453 
               A121036
%Y A101931 Adjacent sequences: A101928 A101929 A101930 this_sequence A101932 A101933 
               A101934
%K A101931 nonn
%O A101931 1,2
%A A101931 Eric Weisstein (eric(AT)weisstein.com), Dec 21, 2004
%E A101931 More terms from Jan Feitsma and Bart Dopheide (dopheide(AT)fmf.nl), Mar 
               10 2005