A349887 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

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

PROG

(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