%I #11 May 17 2013 17:35:03
%S 2,6,11,18,26,36,48,61,75,90,106,123,142,163,185,208,232,257,284,312,
%T 341,371,402,434,467,501,536,573,612,652,693,735,778,822,867,913,960,
%U 1009,1059,1110,1162,1215,1269,1324,1380,1437,1495,1554,1614,1676,1739,1804,1870,1937,2005,2074,2144
%N Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives Q.
%C In contrast to A225376-A225378, here it is not required (and not true) that each number should appear just once in P union Q union R. On the other hand, again in contrast to A225376-A225378, here it is obvious that P, Q, R are infinite.
%C The first three numbers that are repeated are 284, 2074, 3500, which appear in both P and Q. There may be no others. Of course R is disjoint from P and Q, by definition.
%p See A225385.
%Y Cf. A225385, A225387, A005228, A030124, A037257, A225376, A225377, A225378.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, May 15 2013