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A383246 Positive integers without the digit 0 such that every even digit except the rightmost is immediately followed by a smaller digit.

%I A383246 #14 Apr 30 2025 11:08:50
%S A383246 1,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,21,31,32,33,34,35,36,37,
%T A383246 38,39,41,42,43,51,52,53,54,55,56,57,58,59,61,62,63,64,65,71,72,73,74,
%U A383246 75,76,77,78,79,81,82,83,84,85,86,87,91,92,93,94,95,96,97,98,99
%N A383246 Positive integers without the digit 0 such that every even digit except the rightmost is immediately followed by a smaller digit.
%C A383246 Conjecture: these are the terms of A342043, sorted.
%H A383246 Paolo Xausa, <a href="/A383246/b383246.txt">Table of n, a(n) for n = 1..10000</a>
%t A383246 A383246Q[k_] := FreeQ[#, 0] && FreeQ[Partition[#, 2, 1], {i_?EvenQ, j_} /; j >= i] &  [IntegerDigits[k]];
%t A383246 Select[Range[200], A383246Q]
%o A383246 (Python)
%o A383246 def ok(n):
%o A383246     s = str(n)
%o A383246     return "0" not in s and all(d not in "02468" or s[i]<d for i, d in enumerate(s, 1) if i < len(s))
%o A383246 print([k for k in range(100) if ok(k)]) # _Michael S. Branicky_, Apr 28 2025
%Y A383246 Cf. A342043, A383245 (complement).
%Y A383246 Cf. A377912, A382465, A382624, A382938, A383062, A383248, A383250, A383501.
%K A383246 nonn,base,easy
%O A383246 1,2
%A A383246 _Paolo Xausa_, Apr 20 2025