%I #17 Feb 23 2023 11:28:35
%S 951,1339849258,9569810428334921,19132121777295048135244,
%T 81963468350564671450762204559,1287504688596138051498743351405666674,
%U 23901655485793371607250742363386659018053931
%N Numerators of rational approximation to Pi/4 from Machins's formula.
%C Machin's formula: Pi/4 = 4*arctan(1/5) - arctan(1/239).
%C Denominators are given in A096955.
%D W. Walter, Analysis I (in German), Springer, 3. Auflage, 1992; p. 216.
%H Wolfdieter Lang, <a href="/A096954/a096954.txt">More comments</a>.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MachinsFormula.html">Machin's Formula</a>.
%F a(n)=numerator(M(n)), with M(n)=4*arctan(1/5, n) - arctan(1/239, n) with arctan(x, n):=sum((((-1)^k)*x^(2k+1))/(2*k+1), k=0..n).
%e a(2)/A096955(2) = 9569810428334921/12184551018734375 = .78540...
%Y Cf. A003881, A096955.
%K nonn,frac,easy
%O 0,1
%A _Wolfdieter Lang_, Jul 23 2004