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

1,1

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

Prog

(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

Crossrefs

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

Sequence in context: A009005 A362018 A138884 * A299489 A039231 A194387

Adjacent sequences: A008518 A008519 A008520 * A008522 A008523 A008524

Keyword

nonn,word,fini,full

Author

N. J. A. Sloane

Status

approved