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 A158899 #11 Feb 23 2015 00:24:26 %S A158899 14,34,38,46,58,94,118,122,194,218,226,262,298,334,358,362,386,446, %T A158899 458,466,514,526,538,626,674,734,758,766,778,838,866,922,974,982,998, %U A158899 1006,1018,1082,1142,1154,1186,1238,1294,1318,1402,1418,1454,1486,1622,1642 %N A158899 These are numbers n such that the reciprocal, 1/n, is a repeating fraction whose period is n/2 - 1. %C A158899 These numbers relate to the long period primes, those that for 1/m the period is m-1 (sequence A006883) in that by multiplying each term in the long period primes by 2, this sequence is generated. %o A158899 (PARI) forstep(n=2, 2e3, 2, if ((setminus(Set(factor(n)[,1]), Set([2,5])) != []) && (znorder(Mod(10, n/2^valuation(n, 2)/5^valuation(n, 5))) + 1 == n/2), print1(n, ", "));); \\ _Michel Marcus_, Feb 24 2013 %Y A158899 Cf. A006883, A007732, A085837, A121090. %K A158899 nonn,base %O A158899 1,1 %A A158899 _Robert Hutchins_, Mar 29 2009 %E A158899 More terms and edited by _Michel Marcus_, Feb 24 2013