A382623 Positive integers that contain an even digit d immediately preceded by a digit <= d.

12, 14, 16, 18, 22, 24, 26, 28, 34, 36, 38, 44, 46, 48, 56, 58, 66, 68, 78, 88, 100, 102, 104, 106, 108, 112, 114, 116, 118, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 134, 136, 138, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 156, 158, 160, 161, 162, 163

Offset: 1

Author

Paolo Xausa, Apr 01 2025

Keywords

• nonn
• base
• easy

Comments

Conjecture: these are the numbers missing from A382621.

Links

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

Crossrefs

Cf. A347298, A382464, A382621, A382624 (complement).

Programs

Mathematica

A382623Q[k_] := MemberQ[Partition[IntegerDigits[k], 2, 1], {i_, j_?EvenQ} /; i <= j];
Select[Range[200], A382623Q]

Python

def ok(n):
    s = str(n)
    return any(s[i+1] >= s[i] for i in range(len(s)-1) if s[i+1] in "02468")
print([k for k in range(1, 164) if ok(k)]) # Michael S. Branicky, Apr 03 2025