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A138890 Non-Padovan numbers.

%I A138890 #13 Sep 17 2024 10:36:35
%S A138890 6,8,10,11,13,14,15,17,18,19,20,22,23,24,25,26,27,29,30,31,32,33,34,
%T A138890 35,36,38,39,40,41,42,43,44,45,46,47,48,50,51,52,53,54,55,56,57,58,59,
%U A138890 60,61,62,63,64,66,67,68,69,70,71,72,73,74
%N A138890 Non-Padovan numbers.
%C A138890 Natural numbers that are not in the Padovan sequence A000931.
%H A138890 Michael De Vlieger, <a href="/A138890/b138890.txt">Table of n, a(n) for n = 1..10000</a>
%H A138890 Chai Wah Wu, <a href="https://arxiv.org/abs/2409.05844">Algorithms for complementary sequences</a>, arXiv:2409.05844 [math.NT], 2024.
%t A138890 Complement[Range[0, Max[#]], #] &@ Union@ LinearRecurrence[{0, 1, 1}, {1, 0, 0}, 23] (* _Michael De Vlieger_, Sep 17 2024 *)
%o A138890 (Python)
%o A138890 def A138890(n):
%o A138890     def f(x):
%o A138890         if x<=1: return n+1
%o A138890         a, b, c, d = 1, 1, 1, 0
%o A138890         while c<=x:
%o A138890             a, b, c = b, c, a+b
%o A138890             d += 1
%o A138890         return n+d-1
%o A138890     m, k = n, f(n)
%o A138890     while m != k: m, k = k, f(k)
%o A138890     return m # _Chai Wah Wu_, Sep 10 2024
%Y A138890 Cf. A000931, A001690, A062289, A092460, A134816, A138836, A138888, A138891.
%K A138890 easy,nonn
%O A138890 1,1
%A A138890 _Omar E. Pol_, Apr 05 2008