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A305849 Positions of 2 in the difference sequence of A305847.

%I A305849 #14 Sep 01 2018 22:28:57
%S A305849 3,6,9,11,14,17,19,22,25,27,30,32,35,38,40,43,46,48,51,53,56,59,61,64,
%T A305849 67,69,72,74,77,80,82,85,87,90,93,95,98,101,103,106,108,111,114,116,
%U A305849 119,122,124,127,129,132,135,137,140,142,145,148,150,153,156,158
%N A305849 Positions of 2 in the difference sequence of A305847.
%C A305849 This is also the sequence of positions of 3 in the difference sequence of A305848.
%H A305849 Clark Kimberling, <a href="/A305849/b305849.txt">Table of n, a(n) for n = 1..3000</a>
%e A305849 A305837 = (1,2,3,5,6,7,9,10,11,13,14,16, ...);
%e A305849 differences: (1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, ...);
%e A305849 positions of 2: (3,6,9,11,14, ...).
%t A305849 mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
%t A305849 u = 5; v = 5; z = 220;
%t A305849 c = {v}; a = {1}; b = {Last[c] - Last[a]};
%t A305849 Do[AppendTo[a, mex[Flatten[{a, b}], Last[a]]];
%t A305849   AppendTo[c, u Length[c] + v];
%t A305849   AppendTo[b, Last[c] - Last[a]], {z}];
%t A305849 c = Flatten[Position[Differences[a], 2]];
%t A305849 a  (* A305847 *)
%t A305849 b  (* A305848 *)
%t A305849 c  (* A305849 *)
%t A305849 (* _Peter J. C. Moses_, May 30 2018 *)
%Y A305849 Cf. A001622, A305847, A305848.
%K A305849 nonn,easy
%O A305849 1,1
%A A305849 _Clark Kimberling_, Jun 11 2018