This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A299616 #9 Feb 16 2025 08:33:53 %S A299616 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, %T A299616 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, %U A299616 4,4,9,9,9,0,6,9,6,4,1,8,0,5,4,2,7,4 %N 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. %C A299616 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. %H A299616 G. C. Greubel, <a href="/A299616/b299616.txt">Table of n, a(n) for n = 1..10000</a> %H A299616 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a> %e A299616 e^(W(1) + W(2)) = 4.13608129477801994342... %t A299616 w[x_] := ProductLog[x]; x = 1; y = 2; N[E^(w[x] + w[y]), 130] (* A299616 *) %t A299616 RealDigits[2/(LambertW[1]*LambertW[2]), 10, 100][[1]] (* _G. C. Greubel_, Mar 03 2018 *) %o A299616 (PARI) 2/(lambertw(1)*lambertw(2)) \\ _G. C. Greubel_, Mar 03 2018 %Y A299616 Cf. A299613, A299615. %K A299616 nonn,cons,easy %O A299616 1,1 %A A299616 _Clark Kimberling_, Mar 01 2018