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A299632
Decimal expansion of 2*W(e/2), where W is the Lambert W function (or PowerLog); see Comments.
4
1, 3, 7, 0, 1, 5, 3, 8, 8, 4, 3, 0, 9, 1, 8, 7, 8, 9, 2, 0, 5, 6, 4, 9, 8, 9, 6, 1, 0, 7, 5, 2, 6, 0, 3, 7, 6, 8, 2, 8, 1, 1, 1, 4, 3, 1, 3, 6, 1, 6, 4, 1, 0, 6, 7, 0, 8, 1, 9, 6, 0, 3, 0, 9, 9, 7, 5, 0, 0, 7, 7, 5, 7, 0, 2, 2, 3, 7, 6, 2, 9, 5, 6, 2, 3, 9
OFFSET
0,2
COMMENTS
The Lambert W function satisfies the functional equations
W(x) + W(y) = W(x*y(1/W(x) + 1/W(y)) = log(x*y)/(W(x)*W(y)) for x and y greater than -1/e, so that 2*W(3/2) =W(e^2/2)/(1/W(e/2)) = 2 - log(4) - 2 log(W(e/2)). See A299613 for a guide to related sequences.
LINKS
Eric Weisstein's World of Mathematics, Lambert W-Function
EXAMPLE
2*W(e/2) = 1.3701538843091878920564989610752603...
MATHEMATICA
w[x_] := ProductLog[x]; x = E/2; y = E/2; u = N[w[x] + w[y], 100]
RealDigits[u, 10][[1]] (* A299632 *)
PROG
(PARI) 2*lambertw(exp(1)/2) \\ Altug Alkan, Mar 13 2018
CROSSREFS
Sequence in context: A261873 A293525 A016617 * A249186 A118746 A181913
KEYWORD
nonn,cons,easy
AUTHOR
Clark Kimberling, Mar 13 2018
STATUS
approved