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%I #11 Jun 10 2024 00:03:57
%S 2,6,7,4,4,3,7,7,8,1,3,8,3,5,4,4,2,7,8,7,9,8,0,3,7,5,6,1,1,5,9,2,5,3,
%T 7,2,5,3,5,1,5,8,8,0,4,8,6,9,0,3,1,0,0,6,9,4,8,2,5,9,0,5,0,3,6,1,4,5,
%U 1,8,6,1,4,1,8,9,7,6,6,1,1,8,7,8,9,7,5,3,6,2
%N Decimal expansion of Product_{n>=1} cos(Pi/(2*n+1)).
%F this * A365255 = A085365.
%e 0.2674437781383544278798037561159253725...
%o (PARI) exp(sumpos(n=1, log(cos(Pi/(2*n+1))))) \\ _Michel Marcus_, Aug 29 2023
%Y Cf. A085365, A365255.
%K nonn,cons
%O 0,1
%A _R. J. Mathar_, Aug 29 2023