

A006933


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


9



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

Invented by N. J. A. Sloane circa 1990.
Theorem (N. J. A. Sloane): In English every odd number contains an `e'.
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 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

Table of n, a(n) for n=1..60.
Author?, What comes next? in Science News for Kids.
Eric Weisstein's World of Mathematics, Eban Number


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]];  from Sergei Haller (sergei(AT)sergeihaller.de), Dec 21 2006


CROSSREFS

Cf. A082504.
Sequence in context: A106274 A204661 A077633 * A046847 A121069 A100838
Adjacent sequences: A006930 A006931 A006932 * A006934 A006935 A006936


KEYWORD

word,nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from WG Zeist, Aug 28 2012


STATUS

approved



