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 A225377 #23 Feb 11 2015 23:11:29 %S A225377 4,6,9,16,24,34,46,59,73,88,105,123,142,163,185,208,233,259,286,314, %T A225377 343,373,404,436,469,504,541,579,618,658,699,741,784,828,873,920,968, %U A225377 1017,1067,1118,1170 %N A225377 Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,5,11, Q starts with 4,6, R starts with 2; at each stage the smallest number not yet present in P,Q,R is appended to R; every number appears exactly once in the union of P,Q,R. Sequence gives Q. %C A225377 P can be extended for 10^6 terms, but it is not known if P,Q,R can be extended to infinity. %C A225377 A probabilistic argument suggests that P, Q, R are infinite. - _N. J. A. Sloane_, May 19 2013 %H A225377 Christopher Carl Heckman, <a href="/A225377/b225377.txt">Table of n, a(n) for n = 1..10001</a> %e A225377 The initial terms of P, Q, R are: %e A225377 1 5 11 20 36 60 94 140 199 272 360 %e A225377 4 6 9 16 24 34 46 59 73 88 %e A225377 2 3 7 8 10 12 13 14 15 %p A225377 See A225376. %Y A225377 Cf. A225376, A225378, A005228, A030124, A037257. %K A225377 nonn %O A225377 1,1 %A A225377 _N. J. A. Sloane_, May 12 2013, based on email from _Christopher Carl Heckman_, May 06 2013 %E A225377 Corrected and edited by _Christopher Carl Heckman_, May 12 2013