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A099285 Decimal expansion of the exponential integral at 1. 2
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; internal format)
OFFSET

0,1

COMMENTS

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Oct 16 2009: (Start)

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.

(End)

EXAMPLE

I=0.219383934395520273677163775460121649031047293406908207577978613...

MAPLE

Digits:=105: evalf(-Ei(-1)); evalf(Ei(1, 1)); [From Johannes W. Meijer (meijgia(AT)hotmail.com), Oct 16 2009]

MATHEMATICA

RealDigits[ ExpIntegralE[1, 1], 10, 105][[1]]

CROSSREFS

Sequence in context: A095888 A160510 A124776 * A188108 A166890 A197411

Adjacent sequences:  A099282 A099283 A099284 * A099286 A099287 A099288

KEYWORD

cons,nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 08 2004

EXTENSIONS

Definition corrected by Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 26 2009

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Last modified February 15 04:59 EST 2012. Contains 205694 sequences.