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 A099285 Decimal expansion of -Ei(-1), negated exponential integral at -1. 8
 2, 1, 9, 3, 8, 3, 9, 3, 4, 3, 9, 5, 5, 2, 0, 2, 7, 3, 6, 7, 7, 1, 6, 3, 7, 7, 5, 4, 6, 0, 1, 2, 1, 6, 4, 9, 0, 3, 1, 0, 4, 7, 2, 9, 3, 4, 0, 6, 9, 0, 8, 2, 0, 7, 5, 7, 7, 9, 7, 8, 6, 1, 3, 0, 7, 3, 5, 6, 8, 6, 9, 8, 5, 5, 9, 1, 4, 1, 5, 4, 4, 7, 2, 2, 2, 1, 0, 2, 5, 1, 0, 3, 5, 1, 3, 7, 2, 4, 9, 9, 5, 4, 7, 5, 8 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The divergent series g(x=1,m) = 1^m*1! - 2^m*2! + 3^m*3! - 4^m*4! + ..., m=>-1, is closely related to the value of -Ei(-1). We discovered that g(x=1,m) = (-1)^m*(A040027(m) - A000110(m+1)*Ei(1,1)*exp(1)), see A163940. We observe that Ei(1,1) = E(1,1,1) = -Ei(-1) is the constant given above and that Ei(1,1)*exp(1) = A073003 is Gompertz's constant. [Johannes W. Meijer, Oct 16 2009] LINKS G. C. Greubel, Table of n, a(n) for n = 0..10000 Eric Weisstein, MathWorld: Exponential Integral FORMULA -Ei(-n) = Integral_{a=n..Infinity} ( Integral_{b=1..Infinity} 1/e^(a*b) db ) da , n>0. [According to Mathematica, Mats Granvik, May 25 2013] Equals the difference between the absolute values of A239069 and A001620. - R. J. Mathar, Mar 07 2016 EXAMPLE 0.219383934395520273677163775460121649031047293406908207577978613... MAPLE Digits:=105: evalf(-Ei(-1)); evalf(Ei(1, 1)); # Johannes W. Meijer, Oct 16 2009 MATHEMATICA RealDigits[ ExpIntegralE[1, 1], 10, 105][[1]] CROSSREFS Cf. A073003. Sequence in context: A160510 A298738 A124776 * A249264 A188108 A166890 Adjacent sequences:  A099282 A099283 A099284 * A099286 A099287 A099288 KEYWORD cons,nonn AUTHOR Robert G. Wilson v, Oct 08 2004 EXTENSIONS Definition corrected by Johannes W. Meijer, Jul 26 2009 Corrected Name (minus 1, not 1), Stanislav Sykora, May 18 2012 STATUS approved

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Last modified October 16 09:29 EDT 2019. Contains 328056 sequences. (Running on oeis4.)