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 A261827 #12 Feb 16 2025 08:33:27
%S A261827 6,0,3,5,7,1,1,7,1,4,3,0,6,9,2,3,3,3,4,6,2,8,3,9,9,0,5,2,9,2,6,0,9,4,
%T A261827 6,1,8,0,8,0,6,1,7,5,7,4,8,1,3,6,8,9,5,4,6,1,0,7,0,6,6,8,5,6,8,3,6,0,
%U A261827 6,9,2,0,3,4,8,2,2,1,1,6,6,9,3,7,3,9,5,4,6,8,6,6,3,3,3,4,2,3,3,0,5,4,4,2,5
%N A261827 Decimal expansion of the number whose continued fraction expansion consists of the perfect numbers (A000396).
%H A261827 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ContinuedFraction.html">Continued Fraction</a>
%H A261827 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PerfectNumber.html">Perfect Number</a>
%e A261827 6.0357117143069233346283990529260946180806175748136895461...
%t A261827 ind = {1, 2, 3, 4, 6, 7, 8, 11, 18, 24, 28, 31, 98, 111} (* from A016027 *); p = Prime@ ind; pn = (2^p - 1)(2^(p - 1)); RealDigits[ FromContinuedFraction@ pn, 10, 111][[1]] (* _Robert G. Wilson v_, Sep 13 2015 *)
%Y A261827 Cf. A000396, A073821, A073822, A073823, A073824, A052119, A064442.
%K A261827 nonn,cons
%O A261827 1,1
%A A261827 _Ilya Gutkovskiy_, Sep 02 2015