

A006933


'Eban' numbers (the letter 'e' is banned!).
(Formerly M1030)


24



2, 4, 6, 30, 32, 34, 36, 40, 42, 44, 46, 50, 52, 54, 56, 60, 62, 64, 66, 2000, 2002, 2004, 2006, 2030, 2032, 2034, 2036, 2040, 2042, 2044, 2046, 2050, 2052, 2054, 2056, 2060, 2062, 2064, 2066, 4000, 4002, 4004, 4006, 4030, 4032, 4034, 4036, 4040, 4042, 4044, 4046, 4050, 4052, 4054, 4056, 4060, 4062, 4064, 4066, 6000
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OFFSET

1,1


COMMENTS

The first number that would appear in the British Eban list but not the American list is 2*10^21.  Douglas Boffey, Jun 21 2012


REFERENCES

J. C. Hernandez et al., "Characterization of Eban numbers", pp. 197200, Journal of Recreational Mathematics, 31 (3) 20022003.
Georges Perec, La disparition, Editions Gallimard, Paris, 1969; English translation: A Void, Harvill, 1994. (A novel that does not use the letter "e".)
Georges Perec, Les Revenentes [a novel in which the only vowel that appears is 'e'].  From Simon Plouffe, Mar 12 2010
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS



EXAMPLE

2052 is in the sequence because written out in English words, "two thousand fiftytwo", it does not contain a single instance of the letter E.
2053 (two thousand fiftythree) is not in the sequence because written out it contains two instances of E.


PROG

(Magma) [ n : n in [1..100]  forall{ i : i in [1..#seq]  seq[i] in eban[(i1)mod 3+1]} where seq is Intseq(n) ] where eban is [[0, 2, 4, 6], [0, 3, 4, 5, 6], [0]]; // Sergei Haller (sergei(AT)sergeihaller.de), Dec 21 2006
(Haskell)
import Data.Maybe (fromJust)
import Data.Text (Text); import qualified Data.Text as T (unpack)
import Text.Numeral.Grammar.Reified (defaultInflection)
import qualified Text.Numeral.Language.EN as EN  see link
a006933 n = a006933_list !! (n1)
a006933_list = filter (T.all (/= 'e') . numeral) [0..] where
numeral :: Integer > Text
numeral = fromJust . EN.gb_cardinal defaultInflection
(Python)
from num2words import num2words
[n for n in range(6001) if 'e' not in num2words(n)] # Indranil Ghosh, Jul 05 2017
(PARI) is(n)=!setsearch(Set(Vec(English(n))), "e") \\ See A052360 for English().  M. F. Hasler, Apr 01 2019


CROSSREFS



KEYWORD

word,nonn


AUTHOR



EXTENSIONS



STATUS

approved



