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 A087121 #15 Aug 06 2014 17:14:12 %S A087121 1,2,3,4,5,6,7,8,9,19,19,19,19,19,19,19,19,19,19,29,29,29,29,29,29,29, %T A087121 29,29,29,39,39,39,39,39,39,39,39,39,39,49,49,49,49,49,49,49,49,49,49, %U A087121 59,59,59,59,59,59,59,59,59,59,69,69,69,69,69,69,69,69,69,69,79,79,79,79,79,79,79,79,79,79,89,89,89,89,89,89,89,89,89,89,99,99,99,99,99,99,99,99,99,99,199,109,109,109,109,109,109,109,109,109,199,199 %N A087121 Take bounded lunar divisors of n as defined in A087028, add them using lunar addition. See A087082 for their conventional sum. %C A087121 Differs from A087052 after 100 terms. %H A087121 D. Applegate, <a href="/A087061/a087061.txt">C program for lunar arithmetic and number theory</a> [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing] %H A087121 D. Applegate, M. LeBrun and N. J. A. Sloane, <a href="http://arxiv.org/abs/1107.1130">Dismal Arithmetic</a> [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing] %H A087121 <a href="/index/Di#dismal">Index entries for sequences related to dismal (or lunar) arithmetic</a> %Y A087121 Cf. A087061, A087062, A087028, A087083, A087082. %K A087121 nonn,easy %O A087121 1,2 %A A087121 Marc LeBrun and _N. J. A. Sloane_, Oct 21 2003