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 A138863 #8 Mar 14 2020 07:08:43 %S A138863 33,77,3131,1227,8191,1371,5287,2147,2351,6111,1627,1727,6851,5327, %T A138863 1087,1407,4451,2571,1991,2807,4711,3451,2891,4371,4451,4011,8571, %U A138863 5307,5207,5111,7447,1787,1291,4127,8111,6251,1271,4391,9271,1247,2907,1247,3171,1271,2027,1651,3111 %N A138863 Concatenation of first two digits and last two digits of n-th Mersenne prime A000668(n). %H A138863 L. C. Noll, <a href="http://www.isthe.com/chongo/tech/math/prime/mersenne.html">Mersenne Prime Digits</a>. %Y A138863 Cf. A000668, A080173, A104511, A138816, A138817, A138840, A138841, A138862, A138864, A138865, A138866. %K A138863 nonn,base %O A138863 1,1 %A A138863 _Omar E. Pol_, Apr 02 2008 %E A138863 More terms from _Jinyuan Wang_, Mar 14 2020