A349888 Numbers which, when written in English, contain exactly two instances of the letter E.

3, 7, 12, 13, 14, 15, 16, 21, 25, 28, 29, 33, 37, 43, 47, 53, 57, 63, 67, 70, 72, 74, 76, 81, 85, 88, 89, 91, 95, 98, 99, 100, 102, 104, 106, 130, 132, 134, 136, 140, 142, 144, 146, 150, 152, 154, 156, 160, 162, 164, 166, 201, 205, 208, 209, 210, 220, 222, 224, 226, 231, 235, 238, 239

Offset: 1

Author

Eric Angelini, Dec 04 2021

Keywords

• word
• nonn

Examples

			THREE has two Es (and is thus in the sequence), FOUR has no E, FIVE has only one, SIX has none, SEVEN has two Es (and is thus in the sequence). Etc.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006933 ('Eban' numbers) and A349887 (exactly one instance).

Programs

Python

from num2words import num2words
def ok(n): return num2words(n).count("e") == 2
print([k for k in range(311) if ok(k)]) # Michael S. Branicky, Feb 19 2022

Extensions

a(7) = 16 inserted by Michael S. Branicky, Feb 19 2022