A173203 a(n) is the smallest number which has in its English name the letter "e" in the n-th position beginning the count from the end, or -1 if no such number exists.

1, 3, 13, 7, 8, 11, 21, 17, 23, 74, 73, 104, 103, 111, 115, 113, 117, 124, 123, 173, 373, 723, 773, 873, 1111, 1115, 1113, 1117, 1124, 1123, 1173, 1323, 1373, 3373, 7323, 7373, 8373, 11373, 17323, 17373, 23373, 73323, 73373, 103323, 103373, 111373

Offset

1,2

Links

Robert P. P. McKone, Table of n, a(n) for n = 1..58 [corrected by Sean A. Irvine]

Example

a(1) = onE, a(2) = thrEe, a(3) =thirtEen, a(4) = sEven, a(5) = Eight, a(6) = Eleven, etc.

Mathematica

ePos[n_] := Flatten@Position[DeleteCases[Reverse@Characters@IntegerName[n, "Words"], a_ /; MemberQ[{" ", "\[Hyphen]"}, a]], "e"]; t = {}; i = 1; Monitor[Table[Do[If[MemberQ[ePos[i], n], Return[lst = AppendTo[t, i]; i = 1; lst], i++], \[Infinity]], {n, 1, 47, 1}] // Last, {ProgressIndicator[n, {1, 47}], n, i}] (* Robert P. P. McKone, Feb 07 2022 *)

Crossrefs

Cf. A164790 ("e" in n-th position).

Cf. A173204 (similar for "n"), A173206 (similar for "t").

Sequence in context: A326609 A376022 A230362 * A140445 A320039 A242173

Adjacent sequences: A173200 A173201 A173202 * A173204 A173205 A173206

Keyword

nonn,word

Author

Claudio Meller, Feb 12 2010

Extensions

More terms from Robert P. P. McKone, Feb 08 2022

a(25) corrected by Sean A. Irvine, Jan 28 2026

Status

approved