I have just found and entry on OEIS for the general formula for the first proble... | Hacker News

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		bobby07 on Oct 17, 2011 \| parent \| context \| favorite \| on: "Embarrassing" open problems in maths I have just found and entry on OEIS for the general formula for the first problem. http://oeis.org/A000055 G.f.: A(x) = 1 + T(x)-T^2(x)/2+T(x^2)/2, where T(x) = x + x^2 + 2*x^3 + … is g.f. for A000081 I havent checked it, I presume its wrong tho?

Someone on Oct 17, 2011 [–]

The original article asks for a closed-form solution. "Closed-form" is not precisely defined (http://en.wikipedia.org/wiki/Closed-form_expression, http://...), but I do not think anybody would call that a closed-form solution.

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