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, 1103, 1111, 1115, 1113, 1117, 1124, 1123, 1173, 1323, 1373, 3373, 7323, 7373, 8373, 11373, 17323, 17373, 23373, 73323, 73373, 103323, 103373, 111373

Offset: 1

Author

Claudio Meller, Feb 12 2010

Keywords

• nonn
• word

Examples

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

Links

• Robert P. P. McKone, Table of n, a(n) for n = 1..58

Crossrefs

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

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

Programs

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 *)

Extensions

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