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 A121239 #8 Sep 03 2024 15:04:01
%S A121239 7,2,8,1,7,1,8,1,7,1,5,4,0,9,5,4,7,6,4,6,3,9,7,1,2,5,2,8,6,4,7,3,3,7,
%T A121239 5,0,2,2,4,2,7,5,2,9,0,6,3,0,0,0,4,0,4,2,5,0,3,3,0,3,2,3,7,2,2,7,5,9,
%U A121239 2,3,3,6,9,6,4,6,4,5,2,4,0,5,4,2,8,6,1,7,8,2,1,4,7,4,8,3,3,5,7,2,5,7,2,5,3
%N A121239 Decimal expansion of 10-e.
%e A121239 7.28171817154095476...
%o A121239 (PARI) {d=104; default(realprecision,d+1); print(k=10-exp(1)); for(c=0,d,z=floor(k); print1(z,","); k=10*(k-z))} \\ _Klaus Brockhaus_, Sep 09 2006
%Y A121239 Cf. A030644, A087654.
%K A121239 nonn,cons
%O A121239 1,1
%A A121239 _Joost de Winter_, Sep 06 2006
%E A121239 More terms from _Klaus Brockhaus_, Sep 09 2006