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 A372804 #12 May 20 2024 03:01:29
%S A372804 1,1,1,2,1,9,5,1,2,1,9,5,1,2,1,9,5,1,2,1,9,5,1,2,1,9,5,1,2,2,0,4,9,7,
%T A372804 3,0,9,2,2,7,9,8,3,3,1,2,3,0,3,3,4,3,4,2,6,8,9,1,3,7,9,4,3,8,2,9,8,8,
%U A372804 2,3,5,9,1,3,9,7,7,2,6,2,4,1,7,4,7,8,6,6,4,2
%N A372804 Decimal expansion of Sum_{k >= 1, A034887(k) even} 1/2^k.
%H A372804 Paolo Xausa, <a href="/A372804/b372804.txt">Table of n, a(n) for n = 0..10000</a>
%H A372804 J. M. Borwein and P. B. Borwein, <a href="https://doi.org/10.2307/2324993">Strange Series and High Precision Fraud</a>, The American Mathematical Monthly, Vol. 99, No. 7 (1992), pp. 622-640.
%F A372804 Approximately 114/1025, correct to 30 digits: see Example 4.2 (b) in Borwein and Borwein (1992), p. 634.
%e A372804 0.1112195121951219512195121951220497309227983312303343426891...
%t A372804 First[RealDigits[Sum[If[OddQ[IntegerLength[2^k]], 0, 1/2^k], {k, 350}], 10, 100]]
%Y A372804 Cf. A000079, A034887.
%K A372804 nonn,cons
%O A372804 0,4
%A A372804 _Paolo Xausa_, May 13 2024