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 A099969 #14 Aug 02 2025 17:04:28
%S A099969 2,10,26,58,122,1146,5242,13434,46202,177274,701562,1750138,18527354,
%T A099969 52081786,186299514,454734970,4749702266,21929571450,56289309818,
%U A099969 331167216762,880923030650,1980434658426,6378481169530,15174574191738
%N A099969 Write 1/e as a binary fraction; read this from left to right and whenever a 1 appears, note the integer formed by reading leftwards from that 1.
%e A099969 1/e = 0.367879441171442321595523770161460867445811131031767834507... = 0.010111100010110101011000110110001011001110111100110111110001101010111010110111 in binary.
%e A099969 From the binary expansion we get 10 = 2, 1010 = 10, 11010 = 26, 111010 = 58, 1111010 = 122, etc.
%t A099969 d = 100; l = First[RealDigits[N[1/E, d], 2]]; Do[m = Take[l, n]; k = Length[m]; If[m[[k]] == 1, Print[2*FromDigits[Reverse[m], 2]]], {n, 1, d}] (* _Ryan Propper_, Aug 18 2005 *)
%Y A099969 Cf. A068985, A099970, A099971, A099972, A099973, A099974.
%K A099969 nonn,easy
%O A099969 0,1
%A A099969 _N. J. A. Sloane_, Nov 13 2004, based on correspondence from _Artur Jasinski_, Mar 25 2003
%E A099969 More terms from _Ryan Propper_, Aug 18 2005