cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 11 results. Next

A006933 'Eban' numbers (the letter 'e' is banned!).

Original entry on oeis.org

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
Offset: 1

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Author

Keywords

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
A085513(a(n)) = 0. - Reinhard Zumkeller, Jan 23 2015

Examples

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

References

  • J. C. Hernandez et al., "Characterization of Eban numbers", pp. 197-200, Journal of Recreational Mathematics, 31 (3) 2002-2003.
  • 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).

Crossrefs

Cf. A082504.
Cf. A085513, A008520 (complement), A008521 (ban o), A008523 (ban t), A089589 (ban i), A089590 (ban u), A014254 (a French version), A287876 (a Hebrew version).
Cf. A008537 (without 'n'), A072956 (turban numbers: without r, t or u), A072957 (urban numbers: without r or u), A089589 (without 'i').

Programs

  • 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 !! (n-1)
    a006933_list = filter (T.all (/= 'e') . numeral) [0..] where
       numeral :: Integer -> Text
       numeral = fromJust . EN.gb_cardinal defaultInflection
    -- Reinhard Zumkeller, Jan 23 2015
    
  • Magma
    [ n : n in [1..100] | forall{ i : i in [1..#seq] | seq[i] in eban[(i-1)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)sergei-haller.de), Dec 21 2006
    
  • PARI
    is(n)=!setsearch(Set(Vec(English(n))), "e") \\ See A052360 for English(). - M. F. Hasler, Apr 01 2019
  • Python
    from num2words import num2words
    [n for n in range(6001) if 'e' not in num2words(n)] # Indranil Ghosh, Jul 05 2017
    

Extensions

More terms from WG Zeist, Aug 28 2012
More cross-references from M. F. Hasler, Apr 01 2019

A008522 Numbers whose American English name contains the letter 't'.

Original entry on oeis.org

2, 3, 8, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77
Offset: 1

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Author

Keywords

Examples

			8 = eigh{t}.
		

Crossrefs

Cf. A008519 (o), A008520 (e), A008536 (n), A008538 (s), A008540 (f), A008553 (y).

Programs

  • Mathematica
    A008522Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"t"];Select[Range[0,200],A008522Q] (* Paolo Xausa, Aug 12 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A008536 Numbers whose American English name contains the letter 'n'.

Original entry on oeis.org

1, 7, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 37, 39, 41, 47, 49, 51, 57, 59, 61, 67, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 87, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107
Offset: 1

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Author

Keywords

Crossrefs

Cf. A008519 (o), A008520 (e), A008522 (t), A008538 (s), A008540 (f), A008553 (y).

Programs

  • Mathematica
    A008536Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"n"];Select[Range[0,200],A008536Q] (* Paolo Xausa, Aug 12 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A008519 Numbers whose American English name contains the letter 'o'.

Original entry on oeis.org

0, 1, 2, 4, 14, 21, 22, 24, 31, 32, 34, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 54, 61, 62, 64, 71, 72, 74, 81, 82, 84, 91, 92, 94, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123
Offset: 1

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Author

Keywords

Crossrefs

Cf. A008520 (e), A008522 (t), A008536 (n), A008538 (s), A008540 (f), A008553 (y).

Programs

  • Mathematica
    A008519Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"o"];Select[Range[0,200],A008519Q] (* Paolo Xausa, Aug 10 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A008538 Numbers whose American English name contains the letter 's'.

Original entry on oeis.org

6, 7, 16, 17, 26, 27, 36, 37, 46, 47, 56, 57, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 86, 87, 96, 97, 106, 107, 116, 117, 126, 127, 136, 137, 146, 147, 156, 157, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173
Offset: 1

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Author

Keywords

Crossrefs

Cf. A008519 (o), A008520 (e), A008522 (t), A008536 (n), A008540 (f), A008553 (y).

Programs

  • Mathematica
    A008538Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"s"];Select[Range[0,200],A008538Q] (* Paolo Xausa, Aug 12 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A008540 Numbers whose American English name contains the letter 'f'.

Original entry on oeis.org

4, 5, 14, 15, 24, 25, 34, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 64, 65, 74, 75, 84, 85, 94, 95, 104, 105, 114, 115, 124, 125, 134, 135, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158
Offset: 1

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Author

Keywords

Crossrefs

Cf. A008519 (o), A008520 (e), A008522 (t), A008536 (n), A008538 (s), A008553 (y).

Programs

  • Mathematica
    A008540Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"f"];Select[Range[0,200],A008540Q] (* Paolo Xausa, Aug 12 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A008553 Numbers whose American English name contains the letter 'y'.

Original entry on oeis.org

20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A008519 (o), A008520 (e), A008522 (t), A008536 (n), A008538 (s), A008540 (f).

Programs

  • Mathematica
    A008553Q[n_]:=StringContainsQ[IntegerName[n,"Words"],"y"];Select[Range[0,200],A008553Q] (* Paolo Xausa, Aug 12 2023 *)

Extensions

Name edited by Paolo Xausa, Aug 12 2023

A085513 Number of "e"s in n (in English).

Original entry on oeis.org

1, 1, 0, 2, 0, 1, 0, 2, 1, 1, 1, 3, 2, 2, 2, 2, 2, 4, 3, 3, 1, 2, 1, 3, 1, 2, 1, 3, 2, 2, 0, 1, 0, 2, 0, 1, 0, 2, 1, 1, 0, 1, 0, 2, 0, 1, 0, 2, 1, 1, 0, 1, 0, 2, 0, 1, 0, 2, 1, 1, 0, 1, 0, 2, 0, 1, 0, 2, 1, 1, 2, 3, 2, 4, 2, 3, 2, 4, 3, 3, 1, 2, 1, 3, 1, 2, 1, 3, 2, 2, 1, 2, 1, 3, 1, 2, 1, 3, 2, 2
Offset: 0

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Author

Samuel Thompson (samuelt(AT)ugcs.caltech.edu), Jul 03 2003

Keywords

Comments

a(A006933(n)) = 0; a(A008520(n)) > 0. - Reinhard Zumkeller, Jan 23 2015
a(A006933(n)) = 0; a(A008520(n)) > 0; a(A121065(n)) = n and a(m) != n for m < A121065(n). - Reinhard Zumkeller, Jan 24 2015

Examples

			a(123) = 5 because "onE hundrEd twEnty-thrEE" has 5 e's.
		

Crossrefs

Programs

  • 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
    a085513 = length . filter (== 'e') . T.unpack . numeral where
       numeral :: Integer -> Text
       numeral = fromJust . EN.gb_cardinal defaultInflection
    -- Reinhard Zumkeller, Jan 23 2015
    
  • Mathematica
    StringCount[IntegerName/@Range[0,99],"e"] (* Ivan N. Ianakiev, Mar 25 2017 *)
  • Python
    from num2words import num2words
    def A085513(n):
        return num2words(n).count('e') # Chai Wah Wu, Dec 20 2019

A121065 a(n) is the smallest number in English which contains n letter 'E's.

Original entry on oeis.org

2, 0, 3, 11, 17, 111, 117, 317, 1317, 3317, 11317, 17317, 111317, 117317, 317317, 1317317, 3317317, 11317317, 17317317, 111317317, 117317317, 317317317, 1317317317, 3317317317, 11317317317, 17317317317, 111317317317, 117317317317, 317317317317, 1317317317317
Offset: 0

Views

Author

Ray G. Opao, Aug 10 2006

Keywords

Comments

4, 5, 6, 8, 9 never appear in any of these numbers because in each case there is a smaller digit with the same number of e's. 2 (the smallest number with no e's) never appears in any term after a(0). - Sean A. Irvine, Nov 10 2009
A085513(a(n)) = n and A085513(m) != n for m < a(n). - Reinhard Zumkeller, Jan 24 2015

Examples

			a(2) = THREE, which has two Es.
		

Crossrefs

Cf. A085513, A008520, A006933. Variant of A036448.

Programs

  • Haskell
    import Data.List (elemIndex); import Data.Maybe (fromJust)
    a121065 = fromJust . (`elemIndex` a085513_list)
    -- Reinhard Zumkeller, Jan 24 2015

Formula

From Chai Wah Wu, Dec 20 2019: (Start)
a(n) = a(n-1) + 1000*a(n-7) - 1000*a(n-8) for n > 9 (conjectured).
G.f.: (-1000*x^9 + 3000*x^8 - 1800*x^7 + 6*x^6 + 94*x^5 + 6*x^4 + 8*x^3 + 3*x^2 - 2*x + 2)/((x - 1)*(1000*x^7 - 1)) (conjectured). (End)

Extensions

More terms Sean A. Irvine, Nov 10 2009
a(19) - a(21) added by Reinhard Zumkeller, Jan 24 2015
a(22) - a(29) from Chai Wah Wu, Dec 20 2019

A095790 Numbers whose name in English contains an "r".

Original entry on oeis.org

3, 4, 13, 14, 23, 24, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 53, 54, 63, 64, 73, 74, 83, 84, 93, 94, 103, 104, 113, 114, 123, 124, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148
Offset: 1

Views

Author

Michael Joseph Halm, Jul 10 2004

Keywords

Comments

A008520 are numbers which contain an "e", A008540 an "f", A011538 a "g", A008536 an "n", A008519 an "o", A008538 an "s", A008522 a "t", A011534 a "u", A011532 a "w", A011536 an "x" and A008553 a "y"

Examples

			a(1) = 3 because "three" contains an "r", 0, 1 and 2 do not
		

Crossrefs

Showing 1-10 of 11 results. Next