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