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 A089784 #17 Dec 18 2022 20:01:08
%S A089784 81,83,87,89,71,73,77,79,51,53,57,59,31,33,37,39,11,13,17,19,31,33,37,
%T A089784 39,71,73,77,79,91,93,97,99,31,33,37,39,91,93,97,99,11,13,17,19,71,73,
%U A089784 77,79,11,13,17,19,31,33,37,39,71,73,77,79,31,33,37,39,91,93,97,99,11
%N A089784 A nonsense sequence.
%t A089784 a={1, 3, 7, 9};
%t A089784 Flatten[Table[Mod[Abs[10-Prime[n]], 10]*10+a, {n, 50}]]
%Y A089784 Cf. A007652, A131712.
%Y A089784 Cf. A089787 (essentially the same).
%K A089784 nonn,base,less,uned
%O A089784 1,1
%A A089784 _Roger L. Bagula_, Jan 09 2004