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Decimal expansion of Sum_{k>=0} (-1)^k / ((k+1)*(2*k)!).
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%I #15 Jul 03 2024 08:01:04

%S 7,6,3,5,4,6,5,8,1,3,5,2,0,7,2,4,4,8,1,0,6,8,7,7,8,5,8,1,4,6,5,5,1,2,

%T 0,6,7,0,9,7,4,6,9,6,2,8,3,2,5,8,6,5,8,6,6,8,5,6,9,7,9,3,0,7,4,6,0,2,

%U 1,5,9,8,3,3,1,4,2,2,8,6,6,9,3,3,1,8

%N Decimal expansion of Sum_{k>=0} (-1)^k / ((k+1)*(2*k)!).

%F Equals 2*(A143623 - 1).

%e 0.7635465813520724481068778581465512067097...

%p hypergeom([1], [1/2, 2], -1/4) ; evalf(%) ; # _R. J. Mathar_, Jul 03 2024

%t s = N[Sum[(-1)^k/((k + 1) (2 k)!), {k, 0, Infinity}], 120]

%t First[RealDigits[s]]

%Y Cf. A143623, A334397.

%K nonn,cons

%O 0,1

%A _Clark Kimberling_, Apr 24 2024