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 A216147 #5 Sep 03 2012 03:15:45 %S A216147 3,3,9,55,513,6251,93313,1647087,33554433,774840979,20000000001, %T A216147 570623341223,17832200896513,605750213184507,22224013651116033, %U A216147 875787780761718751,36893488147419103233,1654480523772673528355,78692816150593075150849,3956839311320627178247959 %N A216147 2*n^n + 1. %Y A216147 See A216148 for primes in this sequence, A110932 for the corresponding indices. %K A216147 nonn %O A216147 0,1 %A A216147 _M. F. Hasler_, Sep 02 2012