A103154 Each letter appears an even number of times in the English names for 1 through n taken together (names without "and").

119, 139, 159, 179, 199, 319, 339, 359, 379, 399, 519, 539, 559, 579, 599, 719, 739, 759, 779, 799, 919, 939, 959, 979, 999, 1119, 1139, 1159, 1179, 1199, 1319, 1339, 1359, 1379, 1399, 1519, 1539, 1559, 1579, 1599, 1719, 1739, 1759, 1779, 1799, 1919

Offset: 1

Author

David W. Wilson, Jan 24 2005

Keywords

• nonn
• word

Examples

			Together the English words for 1 through 119 contain 40 d's, 218 e's, 56 f's, 22 g's, 64 h's, 100 i's, 4 l's, 144 n's, 62 o's, 64 r's, 44 s's, 150 t's, 32 u's, 36 v's, 22 w's, 22 x's and 80 y's. All counts are even so 119 is in the sequence.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Programs

Maple

letters:= [$"a".."z"]:
V:= Vector(26):
Res:= NULL: count:= 0:
for n from 1 while count < 100 do
  S:= convert(n,english);
  V:= V + ;
  if andmap(type,V,even) then
    count:= count+1; Res:= Res, n;
  fi
od:
Res; # Robert Israel, Mar 17 2020

Formula

It appears that a(n+5)=a(n)+200. - Robert Israel, Mar 17 2020