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 13 results. Next

A002810 Smallest number containing n syllables in UK English.

Original entry on oeis.org

1, 7, 11, 27, 77, 107, 111, 127, 177, 777, 1127, 1177, 1777, 7777, 11777, 27777, 77777, 107777, 111777, 127777, 177777, 777777, 1127777, 1177777, 1777777, 7777777, 11777777, 27777777, 77777777, 107777777, 111777777, 127777777, 177777777, 777777777
Offset: 1

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Author

Keywords

Comments

This sequence uses UK English as opposed to US English. a(6) = 107 since "one hundred and seven" has six syllables. - N. J. A. Sloane, Nov 24 2009
Because of this convention, we do not have A075774(a(n))=n, since A075774 uses US English, i.e., without the "trailing 'and'". All terms from a(6)=107 on will have this 'and', therefore A075774(a(n)) = n-1 for 5 < n < 18. From a(18)=107777 on, there is a second 'and', etc. See A045736 for the "American English" version, see A001167 for the analog considering the number of words. - M. F. Hasler, Nov 03 2013
From Bernard Schott, Feb 18 2019: (Start)
a(19) = 111777 is precisely the number used for Berry's paradox. In UK English the name of the number 111777 requires 19 syllables -- "one hundred and eleven thousand seven hundred and seventy-seven" -- and it's exactly the smallest number containing 19 syllables in UK English.
The paradox occurs when we consider that this integer is "the least integer not nameable in fewer than nineteen syllables" yet 111777 has just now been defined in eighteen syllables with this last sentence. So there is a contradiction, because the smallest integer expressible in no fewer than nineteen syllables can be expressed in eighteen syllables. This contradiction is Berry's paradox. (End)

Examples

			"One" has one syllable, therefore a(1)=1; a(2)=7 since "seven" is the least number to have two syllables; a(3)=11 because eleven is the first to have 3 syllables.
		

References

  • Rodolfo Kurchan, Mesmerizing Math Puzzles, by Sterling Publications, 2000, p. 18.
  • R. C. Penner, Discrete Mathematics, Proofs Techniques and Mathematical Structures, World Scientific, 1999, Reprinted 2001, p. 97.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books, Revised edition, 1997, p. 171.

Crossrefs

Cf. A045736.

Programs

  • PARI
    A002810(n)={if(n>12, A002810(n-4*n=(n-1)\12*3)*10^n+10^n\9*7, [1, 7, 11, 27, 77, 107, 111, 127, 177, 777, 1127, 1177][n])} \\ Valid up to a(58) (or a(84) when long scale is used). - M. F. Hasler, Nov 03 2013

Formula

a(n+12) = a(n)*1000+777, as long as a(n+12) is less than one quadrillion (whatever scale is used). - M. F. Hasler, Nov 03 2013

Extensions

Edited and extended by M. F. Hasler, Nov 03 2013

A089746 Period 12: repeat (4, 4, 1, 2, 1, 1, 2, 2, 3, 3, 3, 3). (Number of syllables in English name of the months.)

Original entry on oeis.org

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

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Author

Drexel Hallaway (drexel(AT)cs.columbia.edu), Jan 08 2004

Keywords

Comments

Original definition: Number of syllables in English name of n-th month, with comment: Period 12.
The original definition corresponds to the finite subsequence a(1)..a(12). There is no 13th month of the year. If "of the year" is omitted on purpose, there's no reason that the 1st month be January: the first day of the currently used Gregorian calendar was October 15, 1582, so the 1st month should be October. Originally the first month was March (whence the names September, ..., December for the 7th, ..., 10th month) and January was the 11th month. - M. F. Hasler, Feb 25 2018

Examples

			For example, January is pronounced with four syllables: Jan-u-ar-y.
		

References

  • Marilyn vos Savant (marilyn(AT)parade.com), column in Parade magazine, 2003.

Crossrefs

Programs

  • PARI
    a(n)=digits(344121122333)[n%12+1] \\ M. F. Hasler, Feb 25 2018

Formula

G.f.: x*(-3*x^11 - 3*x^10 - 3*x^9 - 3*x^8 - 2*x^7 - 2*x^6 - x^5 - x^4 - 2*x^3 - x^2 - 4*x - 4)/(x^12 - 1). - Chai Wah Wu, Feb 16 2021

Extensions

Thanks to Ray Chandler for supplying the explanation for this sequence.
Edited by M. F. Hasler, Feb 25 2018

A163648 Primes p with a prime number of syllables in their name in American English.

Original entry on oeis.org

7, 11, 13, 17, 19, 23, 29, 31, 41, 43, 53, 59, 61, 83, 89, 107, 113, 127, 137, 157, 167, 173, 179, 197, 227, 257, 271, 307, 313, 337, 347, 367, 373, 379, 397, 419, 457, 467, 479, 487, 547, 557, 571, 587, 607, 613, 619, 647, 673, 701, 709, 733, 739, 743, 751
Offset: 1

Views

Author

Jonathan Vos Post, Aug 02 2009

Keywords

Comments

The word "and" is excluded, 101 is "one hundred one" rather than "one hundred and one."
See A231073 and A231075 for the analogs counting words resp. letters. - M. F. Hasler, Nov 03 2013

Examples

			a(1) = 7, which has a prime number, 2, of syllables sev-en. a(2) = 11, which has a prime number, 3, of syllables e-lev-en.
		

Crossrefs

Programs

Formula

{p in A000040 such that A075774(p) is in A000040}.

Extensions

Extended and edited by Charles R Greathouse IV, Nov 02 2009
Values double-checked by M. F. Hasler, Nov 03 2013

A045736 Smallest positive integer requiring n syllables to pronounce in American English.

Original entry on oeis.org

1, 7, 11, 27, 77, 111, 127, 177, 777, 1127, 1177, 1777, 7777, 11777, 27777, 77777, 111777, 127777, 177777, 777777, 1127777, 1177777, 1777777, 7777777, 11777777, 27777777, 77777777, 111777777, 127777777, 177777777, 777777777, 1127777777, 1177777777, 1777777777
Offset: 1

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Author

Keywords

Comments

Assumes the American usage of billion, trillion, etc. ("short scale"), which makes a difference from a(59) on.
See A002810 for the British English version, which in particular includes the additional "and", e.g., in "one hundred and seven". Therefore the sequences differ from a(6)=111 on, with A002810(6)= 107. - M. F. Hasler, Nov 03 2013

Crossrefs

Cf. A002810.

Programs

  • PARI
    A045736(n)={n>11 || for(k=1,1e5,A075774(k)==n && return(k)); A045736(n-11*n=(n-1)\11)*1000^n+1000^n\9*7 } \\ This code is valid up to n=58 (short scale) or n=82 (long scale). - M. F. Hasler, Nov 03 2013

Formula

a(n) = min{ k | A075774(k)=n }. - M. F. Hasler, Nov 03 2013
a(n+11) = a(n)*1000+777, as long as a(n+11) is less than one quadrillion (whatever scale is used). - M. F. Hasler, Nov 03 2013

A180961 Numbers such that the American English name of the number has four syllables.

Original entry on oeis.org

27, 37, 47, 57, 67, 71, 72, 73, 74, 75, 76, 78, 79, 87, 97, 101, 102, 103, 104, 105, 106, 108, 109, 110, 112, 201, 202, 203, 204, 205, 206, 208, 209, 210, 212, 301, 302, 303, 304, 305, 306, 308, 309, 310, 312, 401, 402, 403, 404, 405, 406, 408, 409, 410, 412
Offset: 1

Views

Author

Kyle Stern, Sep 28 2010

Keywords

Comments

There are a finite number of terms, considering all terms up to 10^66 using English names of large numbers and various conventional extensions thereof (see Wikipedia link). - Michael S. Branicky, May 27 2024

Examples

			27 = "twen-ty sev-en", 101 = "one hun-dred one"
		

Crossrefs

Cf. A075774.

Programs

Formula

A075774(a(n)) = 4. - Michael S. Branicky, May 27 2024

Extensions

Corrected by Kyle Stern, Sep 30 2010

A230956 Semiprimes k with a semiprime number of syllables in their name in American English.

Original entry on oeis.org

57, 74, 87, 106, 111, 121, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 169, 183, 185, 194, 201, 202, 203, 205, 206, 209, 217, 221, 226, 235, 249, 253, 254, 259, 262, 265, 289, 291, 295, 298, 299, 301, 302, 303, 305, 309
Offset: 1

Views

Author

Jonathan Vos Post, Nov 04 2013

Keywords

Comments

This is to A163648 as semiprimes A001358 are to primes A000040.
The word "and" is excluded, 101 is "one hundred one" rather than "one hundred and one."
Number of syllables in n in American English is A075774.
See A231073 and A231075 for prime analogs counting words respectively letters.

Examples

			87 is in the sequence because 87 = 3 * 29 is semiprime, "eighty-seven" has 4 syllables, and 4 = 2^2 is also semiprime.
106 is in the sequence because 106 = 2 * 53 is semiprime and "one hundred six" has semiprime 4 syllables.
111 is in the sequence because 111 = 3 * 37 is semiprime and "one hundred eleven" has semiprime 6 = 2*3 syllables.
		

Crossrefs

Programs

  • Python
    # uses function in A075774
    from sympy import factorint
    def issemiprime(n): return sum(factorint(n).values()) == 2
    def ok(n): return issemiprime(A075774(n)) and issemiprime(n)
    print([k for k in range(310) if ok(k)]) # Michael S. Branicky, May 27 2024

Formula

{k: k is in A001358 and A075774(k) is in A001358}.

Extensions

Corrected and extended by Charles R Greathouse IV, Jan 23 2014

A372807 Numbers whose American English name has exactly three syllables.

Original entry on oeis.org

11, 17, 21, 22, 23, 24, 25, 26, 28, 29, 31, 32, 33, 34, 35, 36, 38, 39, 41, 42, 43, 44, 45, 46, 48, 49, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 63, 64, 65, 66, 68, 69, 70, 81, 82, 83, 84, 85, 86, 88, 89, 91, 92, 93, 94, 95, 96, 98, 99, 100, 200, 300, 400, 500, 600, 800, 900
Offset: 1

Views

Author

Marc Groz, May 13 2024

Keywords

Comments

There are 107 terms, considering all terms up to 10^66 using English names of large numbers and various conventional extensions thereof (see Wikipedia link), since quadrillion, quintillion, etc. each have three or more syllables themselves. Terms like "one googol" (or possibly "a googol"), "two googol," ..., "twelve googol" are unconventional, hence disallowed. - Michael S. Branicky, May 28 2024

Examples

			a(2) = 17 is the second number whose name in American English has exactly three syllables: "seventeen".
		

Crossrefs

Programs

Formula

A075774(a(n)) = 3. - Michael S. Branicky, May 27 2024

A164043 Numbers divisible by the number of syllables in their (American) English name.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 16, 18, 20, 21, 24, 30, 33, 36, 39, 40, 42, 45, 48, 50, 51, 54, 60, 63, 66, 69, 72, 76, 80, 81, 84, 90, 93, 96, 99, 104, 108, 112, 115, 120, 126, 130, 132, 138, 140, 144, 147, 150, 156, 160, 162, 168, 175, 180, 186, 190, 192, 198
Offset: 1

Views

Author

Jonathan Vos Post, Aug 08 2009

Keywords

Comments

The name has no extra "and" syllables, as in 104 being in this sequence because "one hundred four" has 4 syllables (which divides 104) rather than "one hundred and four" which has 5 syllables.

Examples

			a(15) = 21 because "twenty-one" has 3 syllables, and 3*7 = 21.
		

Crossrefs

Cf. A075774, A045736, A002810 (British variant), A163648.

Programs

Formula

{k such that A075774(k)|k}.

Extensions

84 inserted and more terms from Michael S. Branicky, May 27 2024

A231072 Number of words in English spelling of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2
Offset: 0

Views

Author

M. F. Hasler, Nov 03 2013

Keywords

Comments

From a(101) on it must be made precise that this sequence uses the American style ("one hundred one"), as in A052360, and not the British style ("one hundred and one"). The choice of long or short scale does not make a difference since, e.g., the word "milliard" in long scale use would simply be replaced by "billion" in short scale. However, the use of "thousand [million]" instead, would lead to different results for numbers such that floor(n/10^6) mod 10^3 is zero. - M. F. Hasler, Nov 03 2013

Examples

			From "zero" to "twenty", the numbers are written in one word, so a(0..20)=1. "Twenty-one" is the first term to require 2 words, so a(21)=2.
		

Crossrefs

Programs

  • PARI
    a(n)=sum(k=7,#n=Vecsmall(English(n)),n[k-3]<65)+1 \\ See A052360 for English(). Only characters 4,...,length-4 need to be checked for space/hyphen since there is no word with less than 3 letters.

A249030 The difference between the number of letters and the number of syllables in n in English. (Omit "and" in both.)

Original entry on oeis.org

2, 2, 2, 4, 3, 3, 2, 3, 4, 3, 2, 3, 5, 6, 6, 5, 5, 6, 6, 6, 4, 6, 6, 8, 7, 7, 6, 7, 8, 7, 4, 6, 6, 8, 7, 7, 6, 7, 8, 7, 3, 5, 5, 7, 6, 6, 5, 6, 7, 6, 3, 5, 5, 7, 6, 6, 5, 6, 7, 6, 3, 5, 5, 7, 6, 6, 5, 6, 7, 6, 4, 6, 6, 8, 7, 7, 6, 7, 8, 7
Offset: 0

Views

Author

Chris Smith, Oct 27 2014

Keywords

Comments

Take the number of letters in the spelling of a number and subtract the number of syllables in the sounding of that number. For example, zero has four letters and two syllables generating 4-2=2 for the first term. As such it is linked to sequences A005589 and A075774.

Crossrefs

Formula

a(n) = A005589(n) - A075774(n).

Extensions

Corrected a(11) and extended to a(79) by Chris Smith, Mar 16 2015
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