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Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x+1 and x(x+1)/2 are in a.
2

%I #7 Nov 17 2016 12:13:54

%S 1,3,6,7,13,15,21,27,28,31,43,55,57,63,87,91,111,115,120,127,175,183,

%T 223,231,241,255,351,367,378,406,447,463,483,496,511,703,735,757,813,

%U 895,927,946,967,993,1023,1407,1471,1515,1540,1627,1653,1791,1855,1893,1935,1987,2016,2047,2815,2943,3031,3081,3255,3307,3583

%N Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x+1 and x(x+1)/2 are in a.

%C See A191203.

%H Ivan Neretin, <a href="/A191290/b191290.txt">Table of n, a(n) for n = 1..10000</a>

%e 1 -> 3 -> 6,7 -> 13,15,21,28 ->

%t g=11; Union[Flatten[NestList[{1+2#, (#^2+#)/2} &, 1, g]]]

%t (* A191290; use g>9 to get all of first 60 terms *)

%Y Cf. A191203.

%K nonn

%O 1,2

%A _Clark Kimberling_, May 29 2011