A008521 Numbers that do not contain the letter 'o'.

3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 23, 25, 26, 27, 28, 29, 30, 33, 35, 36, 37, 38, 39, 50, 53, 55, 56, 57, 58, 59, 60, 63, 65, 66, 67, 68, 69, 70, 73, 75, 76, 77, 78, 79, 80, 83, 85, 86, 87, 88, 89, 90, 93, 95, 96, 97, 98, 99, 300, 303, 305, 306, 307

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• word
• fini
• full

Comments

There are exactly 454 oban numbers. - Eric W. Weisstein, Nov 09 2003

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..454
• Roel and Bas van Dijk, Numerals package, Hackage (Haskell packages).
• Eric Weisstein's World of Mathematics, Oban Number
• Index entries for sequences related to number of letters in n

Crossrefs

Cf. A006933 (ban e), A089589 (ban i), A008523 (ban t), A089590 (ban u).

Programs

Haskell

import Data.Maybe (fromJust)
import Data.Text (Text); import qualified Data.Text as T (all)
import Text.Numeral.Grammar.Reified (defaultInflection)
import qualified Text.Numeral.Language.EN as EN  -- see link
a008521 n = a008521_list !! (n-1)
a008521_list = filter (T.all (/= 'o') . numeral) [0..] where
   numeral :: Integer -> Text
   numeral = fromJust . EN.gb_cardinal defaultInflection
-- Reinhard Zumkeller, Jan 23 2015

Python

from num2words import num2words
afull = [k for k in range(1000) if "o" not in num2words(k)]
print(afull[:70]) # Michael S. Branicky, Aug 18 2022