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 A061744 #8 Feb 24 2020 08:40:35 %S A061744 1,7,127,511,8191,32767,2097151,33554431,2147483647,8589934591, %T A061744 137438953471,8796093022207,562949953421311,2251799813685247, %U A061744 9223372036854775807,147573952589676412927,590295810358705651711,9444732965739290427391,37778931862957161709567 %N A061744 a(n) = (2^A000959(n)) - 1. %Y A061744 Cf. A000959, A061743, A000668. %K A061744 nonn %O A061744 1,2 %A A061744 _Jason Earls_, May 07 2001