%I A103975
%S A103975 16,240,3360,46816,652080,9082320,126500416,1761923520,24540428880,
%T A103975 341804080816,4760716702560,66308229755040,923554499868016,
%U A103975 12863454768397200,179164812257692800,2495443916839302016
%N A103975 Smaller side in (a,a+1,a+1)-integer triangle with integer area.
%F A103975 a(n) = 15*a(n-1) - 15*a(n-2) + a(n-3) - Max Alekseyev (maxale(AT)gmail.com), 
               May 31 2007
%F A103975 a(n) = 2*A120892(2*n+1) - Max Alekseyev (maxale(AT)gmail.com), May 31 
               2007
%F A103975 a(n)=1/3*((2 - Sqrt(3))^(1 + 2*n) + (2 + Sqrt(3))^(1 + 2*n) - 4) [From 
               Terentyev Oleg (terentyev_math(AT)i.ua), Nov 12 2009]
%t A103975 a[n_] := 1/3 (-4 + (2 - Sqrt[3])^(1 + 2 n) + (2 + Sqrt[3])^(1 + 2 n)); 
               A103975 = Expand[a /@ Range[1, 25]] [From Terentyev Oleg (terentyev_math(AT)i.ua), 
               Nov 12 2009]
%Y A103975 Cf. A102341, A103974, A016064, A011945, A103772.
%Y A103975 Equals (4/3) (A001570(n) - 1).
%Y A103975 Corresponding areas are given by A104008.
%Y A103975 Sequence in context: A119463 A111096 A161591 this_sequence A060198 A097829 
               A010559
%Y A103975 Adjacent sequences: A103972 A103973 A103974 this_sequence A103976 A103977 
               A103978
%K A103975 nonn,new
%O A103975 1,1
%A A103975 Zak Seidov (zakseidov(AT)yahoo.com), Feb 23 2005
%E A103975 More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 24 2005