A382464 Positive integers that contain an even digit d immediately preceded by a digit >= d.

10, 20, 22, 30, 32, 40, 42, 44, 50, 52, 54, 60, 62, 64, 66, 70, 72, 74, 76, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 120, 122, 130, 132, 140, 142, 144, 150, 152, 154, 160, 162, 164, 166, 170, 172, 174, 176, 180

Offset: 1

Author

Paolo Xausa, Mar 28 2025

Keywords

• nonn
• base
• easy

Comments

Conjecture: these are the numbers missing from A382462.

Links

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

Crossrefs

Cf. A382462, A382465 (complement).

Cf. A347298, A382623, A382937, A383061, A383245, A383247, A383249, A383500.

Programs

Mathematica

A382464Q[k_] := MemberQ[Partition[IntegerDigits[k], 2, 1], {i_, j_?EvenQ} /; i >= j];
Select[Range[200], A382464Q]

Python

def ok(n):
    s = str(n)
    return any(d in "02468" and s[i-1]>=d for i, d in enumerate(s) if i > 0)
print([k for k in range(181) if ok(k)]) # Michael S. Branicky, Apr 30 2025