A349887 Numbers which, when written in English, contain exactly one instance of the letter E.

0, 1, 5, 8, 9, 10, 20, 22, 24, 26, 31, 35, 38, 39, 41, 45, 48, 49, 51, 55, 58, 59, 61, 65, 68, 69, 80, 82, 84, 86, 90, 92, 94, 96, 200, 202, 204, 206, 230, 232, 234, 236, 240, 242, 244, 246, 250, 252, 254, 256, 260, 262, 264, 266, 400, 402, 404, 406, 430, 432, 434, 436

Offset: 1

Author

Eric Angelini, Dec 04 2021

Keywords

• word
• nonn

Examples

			ZERO has one E, ONE also, but not TWO (no E) nor THREE (2 Es).
		

Crossrefs

Cf. A006933 ('Eban' numbers).

Programs

Python

from num2words import num2words
def ok(n): return num2words(n).count("e") == 1
print([k for k in range(667) if ok(k)]) # Michael S. Branicky, Dec 04 2021