OFFSET
1,1
EXAMPLE
In the spelling of the name of each term, with spaces and hyphens omitted, each name has an odd number of letters, and the middle letter is "t"; e.g.,
15 = fifTeen
16 = sixTeen
21 = twenTyone
22 = twenTytwo
31 = thirTysix
74 = sevenTyfour
81 = eighTyone
91 = nineTytwo
123 = onehundredTwentythree
1300 = onethousandThreehundred
1813 = onethousandeighThundredthirteen
MATHEMATICA
ok[n_] := Block[{s = StringReplace[ IntegerName[n, "Words"], ", " | " " | "\[Hyphen]" -> ""], k}, k = StringLength[s]; OddQ[k] && StringTake[s, {(k + 1)/2}] == "t"]; Select[Range[3000], ok] (* Giovanni Resta, Jul 30 2019 *)
CROSSREFS
KEYWORD
nonn,word
AUTHOR
Claudio Meller, May 22 2009
EXTENSIONS
Corrected, edited, and extended by Jon E. Schoenfield, Jul 29 2019
STATUS
approved