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A346172
Decimal expansion of Sum_{k>=1} 1/(k! * 2^A006218(k)).
0
5, 6, 7, 8, 7, 9, 3, 1, 9, 5, 9, 3, 4, 0, 4, 4, 3, 8, 5, 2, 2, 0, 4, 2, 2, 9, 4, 8, 7, 7, 7, 3, 9, 7, 2, 7, 9, 9, 2, 0, 7, 5, 3, 7, 0, 9, 4, 6, 8, 2, 5, 3, 3, 9, 8, 9, 4, 3, 8, 8, 8, 6, 4, 4, 6, 9, 4, 8, 2, 7, 3, 0, 6, 9, 3, 8, 1, 7, 0, 2, 2, 2, 9, 6, 7, 6, 5, 3, 4, 9, 2, 0, 4, 4, 4, 7, 7, 2, 8, 2
OFFSET
0,1
COMMENTS
This constant is irrational (Mingarelli, 2013).
LINKS
Angelo B. Mingarelli, Abstract factorials, Notes on Number Theory and Discrete Mathematics, Vol. 19, No. 4 (2013), pp. 43-76 (see p. 61); arXiv preprint, arXiv:0705.4299 [math.NT], 2007-2012.
EXAMPLE
0.56787931959340443852204229487773972799207537094682...
MATHEMATICA
m = Range[100]; RealDigits[Total[1/(m! * 2^Accumulate[DivisorSigma[0, m]])], 10, 100][[1]]
CROSSREFS
Cf. A006218.
Sequence in context: A368121 A368126 A361472 * A114547 A217293 A201971
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Jul 08 2021
STATUS
approved