

A303701


Number of distinct letters in the (American) English name of n, excluding spaces and hyphens.


0



4, 3, 3, 4, 4, 4, 3, 4, 5, 3, 3, 4, 5, 6, 7, 5, 6, 5, 6, 4, 5, 6, 6, 7, 9, 8, 8, 7, 8, 6, 5, 8, 7, 6, 8, 8, 7, 9, 7, 7, 5, 7, 6, 7, 6, 8, 8, 9, 9, 8, 4, 7, 6, 7, 7, 6, 6, 8, 7, 6, 5, 8, 7, 8, 9, 8, 5, 8, 8, 7, 6, 7, 8, 8, 10, 8, 8, 6, 9, 7, 6, 8, 8, 7, 10, 8, 8, 9, 6, 7, 5, 6, 7, 7, 9, 7, 7, 7
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,1


COMMENTS

First occurrence of k=3..23: 1, 0, 8, 13, 14, 25, 24, 74, 112, 127, 125, 165, 265, 1265, 2568, 12468, 1002568, 1001002568, 1000001001002568, 1000000001000001001002568, 1001000000001000001001002568.
Since there are no number words consisting of just one or two letters, nor any number words which contain the letters "j", "k" or "z"; the above list is complete.


LINKS

Table of n, a(n) for n=0..97.


FORMULA

a(n) <= A005589(n).


EXAMPLE

a(7) = 4 since "seven" has 4 distinct letters. (Cf. A005589(7) = 5.)


MATHEMATICA

f[n_] := Length@ Union@ StringPartition[ StringReplace[ IntegerName[n, "Words"], ", "  " "  "\[Hyphen]" > ""], 1]; Array[f, 98, 0]


CROSSREFS

Cf. A005589.
Sequence in context: A188885 A129344 A048853 * A179845 A180217 A270651
Adjacent sequences: A303698 A303699 A303700 * A303702 A303703 A303704


KEYWORD

nonn,word


AUTHOR

Robert G. Wilson v, Apr 29 2018


STATUS

approved



