A377912 - OEIS

%I #33 Nov 29 2024 10:28:11

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,23,24,25,26,27,28,

%T 29,30,31,32,33,34,35,36,37,38,39,45,46,47,48,49,50,51,52,53,54,55,56,

%U 57,58,59,67,68,69,70,71,72,73,74,75,76,77,78,79,89,90,91,92,93,94,95,96,97,98,99,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117

%N Numbers such that every even digit except the last is immediately followed by a strictly larger digit.

%C In other words, numbers that do not contain a pair of successive digits i, j where i is even and j <= i.

%H Paolo Xausa, <a href="/A377912/b377912.txt">Table of n, a(n) for n = 1..10000</a>

%t A377912Q[k_] := Count[Partition[IntegerDigits[k], 2, 1], {i_, j_} /; EvenQ[i] && j <= i] == 0;

%t Select[Range[0, 300], A377912Q] (* _Paolo Xausa_, Nov 28 2024 *)

%o (Python)

%o def ok(n):

%o     s = str(n)

%o     return not any(s[i] in "2468" and s[i+1] <= s[i] for i in range(len(s)-1))

%o print([k for k in range(0, 118) if ok(k)]) # _Michael S. Branicky_, Nov 28 2024

%Y The complement of A347298. Cf. A342042.

%K nonn,base,new

%O 1,3

%A _N. J. A. Sloane_, Nov 27 2024, with thanks to _Paolo Xausa_ for correcting the initial definition.

%E Added 0 to match A342042, and replaced negative definition by a positive one. - _N. J. A. Sloane_, Nov 29 2024