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A089590 Uban numbers (the letter u is banned from the English name of the number). 9
0, 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 75, 76, 77, 78, 79, 80, 81, 82, 83, 85, 86, 87, 88, 89, 90, 91, 92, 93, 95, 96, 97, 98, 99 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
The sequence of uban numbers first differs from A052406 (the numbers not containing the digit 4) at the term 40 (forty), which is a uban number but is not 4-less.
LINKS
Daniel Arribas and Reinhard Zumkeller, Table of n, a(n) for n = 1..1000 (first 89 terms from Daniel Arribas)
Roel and Bas van Dijk, Numerals package, Hackage (Haskell packages)
Eric Weisstein's World of Mathematics, Uban Number
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
a089590 n = a089590_list !! (n-1)
a089590_list = filter (T.all (/= 'u') . numeral) [0..] where
numeral :: Integer -> Text
numeral = fromJust . EN.gb_cardinal defaultInflection
-- Reinhard Zumkeller, Jan 23 2015
(Python)
from num2words import num2words
from itertools import islice, product
def ok(n): return "u" not in num2words(n)
def agen(): # generator of terms < 10**304
base, pows = [k for k in range(1, 1000) if ok(k)], [1]
yield from ([0] if ok(0) else []) + base
for e in range(3, 304, 3):
if "u" not in num2words(10**e)[4:]:
pows = [10**e] + pows
for t in product([0] + base, repeat=len(pows)):
if t[0] == 0: continue
yield sum(t[i]*pows[i] for i in range(len(t)))
print(list(islice(agen(), 100))) # Michael S. Branicky, Aug 19 2022
CROSSREFS
Cf. A052406.
Cf. A006933 (ban e), A089589 (ban i), A008521 (ban o), A008523 (ban t).
Sequence in context: A242410 A258022 A333638 * A052406 A022306 A183298
KEYWORD
nonn,easy,word
AUTHOR
Eric W. Weisstein, Nov 09 2003
EXTENSIONS
a(1) = 0 prepended by Reinhard Zumkeller, Jan 23 2015
STATUS
approved

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Last modified April 16 03:28 EDT 2024. Contains 371696 sequences. (Running on oeis4.)