%I #16 Nov 27 2021 04:52:20
%S 11,27,43,59,75,91,107,123,139,155,171,203,219,235,251,267,283,299,
%T 315,331,347,363,379,395,411,427,459,475,491,507,523,539,555,571,587,
%U 603,619,635,651,667,683,779,795,811,827,843,859,875,891,907,923,939,971
%N Numbers k such that string 2,3 occurs in the base 4 representation of k but not of k1.
%C Members are of form 16k+11, but not all such numbers are in the sequence. The first missing number is 187.
%H Michael S. Branicky, <a href="/A044072/b044072.txt">Table of n, a(n) for n = 1..10000</a>
%t Flatten[Position[Partition[Table[If[MemberQ[Partition[IntegerDigits[n, 4], 2, 1], {2, 3}], 1, 0], {n, 1000}], 2, 1], {0, 1}]] + 1 (* _Vincenzo Librandi_, Aug 19 2015 *)
%o (Python)
%o from sympy.ntheory.factor_ import digits
%o def has23(n): return "23" in "".join(map(str, digits(n, 4)[1:]))
%o def ok(n): return has23(n) and not has23(n1)
%o print([k for k in range(972) if ok(k)]) # _Michael S. Branicky_, Nov 27 2021
%Y Differs from A106839.
%Y Cf. A044453.
%K nonn,base
%O 1,1
%A _Clark Kimberling_
%E a(48) and beyond from _Michael S. Branicky_, Nov 27 2021
