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 A216105 #17 Jan 05 2013 08:17:22 %S A216105 3,0,4,6,5,7,7,9,1,6,7,7,0,1,5,4,7,4,4,6,9,9,5,4,6,7,9,1,7,8,5,2,1,7, %T A216105 6,1,3,0,8,7,9,8,4,3,9,7,2,5,9,4,7,3,3,8,3,4,5,1,5,6,0,2,8,7,7,1,6,2, %U A216105 0,5,8,8,5,1,6,3,3,7,3,7,9,1,7,5,6,8,0,3,1,2,6,2,3,7,1,3,3,6,1,5,5,0,9,9,7,9,4,0,6,9,3,8 %N A216105 [7^(5*10^(n+1)) mod 10^(2n+3) - 1]/(10^(2n+2)) mod 10. %C A216105 7^500 ends in 64030001 %C A216105 7^5000 ends in 5640300001 %C A216105 7^50000 ends in 756403000001 %C A216105 7^500000 ends in 77564030000001 %C A216105 The last digits before the zeros tend to converge to the present sequence. %Y A216105 Cf. A007185, A016090, A091663, A018248, A091664, A018247, A216104. %K A216105 nonn,base %O A216105 1,1 %A A216105 _V. Raman_, Sep 02 2012