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Integer part of the area of integer triangle [A001611(n), A001611(n+1), A001611(n+2)].
2

%I #7 Dec 22 2017 18:53:15

%S 0,1,2,5,9,18,35,71,144,294,601,1231,2526,5191,10672,21950,45159,

%T 92920,191214,393512,809864,1666775,3430425,7060297,14531166,29907455,

%U 61554442,126689294,260747884,536663296,1104544280,2273340315

%N Integer part of the area of integer triangle [A001611(n), A001611(n+1), A001611(n+2)].

%F a(n) = floor(sqrt(s(n) * (s(n)-A001611(n)) * (s(n)-A001611(n+1)) * (s(n)-A001611(n+2)))), where s(n) is the semiperimeter: s(n) = A097280(n)/2.

%K nonn

%O 0,3

%A _Reinhard Zumkeller_, Aug 04 2004