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A297130 Numbers whose base-4 digits d(m), d(m-1),..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.

%I A297130 #4 Jan 14 2018 23:01:23
%S A297130 1,2,3,5,10,15,16,20,21,22,23,26,31,32,37,40,41,42,43,47,48,53,58,60,
%T A297130 61,62,63,64,65,66,67,69,74,79,80,81,82,83,84,85,86,87,88,89,90,91,92,
%U A297130 93,94,95,96,101,104,105,106,107,111,112,117,122,124,125,126
%N A297130 Numbers whose base-4 digits d(m), d(m-1),..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.
%C A297130 These numbers comprise the complement of the set of numbers in the union of A297128 and A297129.
%e A297130 Base-4 digits of 4997: 1,0,3,2,0,1,1, so that 4997 is in the sequence.
%t A297130 a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;
%t A297130 b = 4; t = Table[a[n, b], {n, 1, 10*z}];
%t A297130 u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297128 *)
%t A297130 v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297129 *)
%t A297130 Complement[Range[z], Union[u, v]]  (* A297130 *)
%Y A297130 Cf. A297128, A297129.
%K A297130 nonn,easy,base
%O A297130 1,2
%A A297130 _Clark Kimberling_, Jan 14 2018