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 A191990 #4 Mar 30 2012 18:57:33 %S A191990 0,1,3,6,7,9,12,13,14,18,19,21,27,29,32,33,41,47,49,51,53,54,68,76,82, %T A191990 83,84,87,88,109,123,131,134,137,139,141,143,177,199,213,217,221,227, %U A191990 228,229,233,286,322,344,351,358,366,369,372,374,378,463,521,557 %N A191990 Ordered sequence of nonnegative differences 5f-2g, where f and g are Lucas numbers (A000032 beginning at 1). %t A191990 (See A191988.) %Y A191990 Cf. A191988, A191989, A191991. %K A191990 nonn %O A191990 1,3 %A A191990 _Clark Kimberling_, Jun 20 2011