A383062 Nonnegative integers such that every odd digit except the leftmost is immediately preceded by a smaller digit.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 34, 35, 36, 37, 38, 39, 40, 42, 44, 45, 46, 47, 48, 49, 50, 52, 54, 56, 57, 58, 59, 60, 62, 64, 66, 67, 68, 69, 70, 72, 74, 76, 78, 79, 80, 82, 84, 86, 88, 89, 90

Offset: 1

Author

Paolo Xausa, Apr 18 2025

Keywords

• nonn
• base
• easy

Comments

Conjecture: these are the terms of A383059, sorted.

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A383059, A383061 (complement).

Cf. A377912, A382465, A382624, A382938, A383246, A383248, A383250, A383501.

Programs

Mathematica

A383062Q[k_] := FreeQ[Partition[IntegerDigits[k], 2, 1], {i_, j_?OddQ} /; i >= j];
Select[Range[0, 100], A383062Q]

Python

def ok(n):
    s = str(n)
    return all(s[i+1] > s[i] for i in range(len(s)-1) if s[i+1] in "13579")
print([k for k in range(91) if ok(k)]) # Michael S. Branicky, Apr 19 2025