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 A280730 #4 Jan 09 2017 13:52:21 %S A280730 1,3,6,16,27,39,59,89,189,299,499,799,1799,2899,4899,6999,9999,19999, %T A280730 39999,69999,169999,279999,399999,599999,899999,1899999,2999999, %U A280730 4999999,7999999,17999999,28999999,48999999,69999999,99999999,199999999,399999999,699999999 %N A280730 Partial sums of A278742. %Y A280730 Cf. A278742. %K A280730 nonn,base %O A280730 1,2 %A A280730 _N. J. A. Sloane_, Jan 09 2017