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Numbers which, when written in English, contain exactly one instance of the letter E.
2

%I #11 Dec 04 2021 12:12:20

%S 0,1,5,8,9,10,20,22,24,26,31,35,38,39,41,45,48,49,51,55,58,59,61,65,

%T 68,69,80,82,84,86,90,92,94,96,200,202,204,206,230,232,234,236,240,

%U 242,244,246,250,252,254,256,260,262,264,266,400,402,404,406,430,432,434,436

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

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

%o (Python)

%o from num2words import num2words

%o def ok(n): return num2words(n).count("e") == 1

%o print([k for k in range(667) if ok(k)]) # _Michael S. Branicky_, Dec 04 2021

%Y Cf. A006933 ('Eban' numbers).

%K word,nonn

%O 1,3

%A _Eric Angelini_, Dec 04 2021