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%I #9 Jul 05 2021 03:45:19
%S 2,5,9,0,5,6,1,4,0,6,5,6,6,1,8,0,0,8,3,7,8,7,7,2,4,2,3,0,6,1,7,2,0,2,
%T 1,3,4,6,9,1,0,1,6,8,6,3,8,7,4,0,4,5,2,9,5,6,8,2,2,5,5,6,9,8,7,0,4,0,
%U 5,2,0,7,3,0,6,9,2,4,4,9,9,0,6,9,0,6,7,8,6,5,2,2,6,5,3,0,6,1,6,5
%N Decimal expansion of Sum_{k>=0} 1/(k! * A003266(k)).
%C This constant is irrational (Mingarelli, 2013).
%H Angelo B. Mingarelli, <a href="http://nntdm.net/volume-19-2013/number-4/43-76/">Abstract factorials</a>, Notes on Number Theory and Discrete Mathematics, Vol. 19, No. 4 (2013), pp. 43-76 (see p. 61); <a href="https://arxiv.org/abs/0705.4299">arXiv preprint</a>, arXiv:0705.4299 [math.NT], 2007-2012.
%e 2.59056140656618008378772423061720213469101686387404...
%t RealDigits[Sum[1/(n! * Fibonorial[n]), {n, 0, 50}], 10, 100][[1]]
%o (PARI) f(n) = prod(i=1, n, fibonacci(i)); \\ A003266
%o suminf(k=0, 1/(k!*f(k))) \\ _Michel Marcus_, Jul 05 2021
%Y Cf. A003266, A062073.
%K nonn,cons
%O 1,1
%A _Amiram Eldar_, Jul 02 2021