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A299616
Decimal expansion of e^(W(1) + W(2)) = 2/(W(1)*W(2)), where W is the Lambert W function (or PowerLog); see Comments.
3
4, 1, 3, 6, 0, 8, 1, 2, 9, 4, 7, 7, 8, 0, 1, 9, 9, 4, 3, 4, 2, 5, 8, 6, 5, 2, 2, 5, 7, 6, 0, 9, 1, 2, 5, 8, 4, 2, 1, 0, 1, 4, 8, 4, 5, 4, 0, 4, 1, 3, 0, 1, 4, 9, 5, 9, 2, 3, 9, 4, 5, 8, 0, 2, 7, 3, 6, 0, 4, 4, 9, 9, 9, 0, 6, 9, 6, 4, 1, 8, 0, 5, 4, 2, 7, 4
OFFSET
1,1
COMMENTS
The Lambert W function satisfies the functional equation e^(W(x) + W(y)) = x*y/(W(x)*W(y)) for x and y greater than -1/e, so that e^(W(1) + W(2)) = 2/(W(1)*W(2)). See A299613 for a guide to related constants.
LINKS
Eric Weisstein's World of Mathematics, Lambert W-Function
EXAMPLE
e^(W(1) + W(2)) = 4.13608129477801994342...
MATHEMATICA
w[x_] := ProductLog[x]; x = 1; y = 2; N[E^(w[x] + w[y]), 130] (* A299616 *)
RealDigits[2/(LambertW[1]*LambertW[2]), 10, 100][[1]] (* G. C. Greubel, Mar 03 2018 *)
PROG
(PARI) 2/(lambertw(1)*lambertw(2)) \\ G. C. Greubel, Mar 03 2018
CROSSREFS
Sequence in context: A090724 A343571 A308633 * A134224 A121441 A256243
KEYWORD
nonn,cons,easy
AUTHOR
Clark Kimberling, Mar 01 2018
STATUS
approved