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.

User: Matt Westwood

Matt Westwood's wiki page.

Matt Westwood has authored 5 sequences.

A333904 The smallest number which is the sum of 2 distinct lucky numbers in exactly n different ways.

Original entry on oeis.org

4, 10, 16, 34, 46, 144, 76, 112, 100, 148, 166, 136, 202, 226, 238, 268, 298, 304, 310, 352, 400, 430, 490, 592, 634, 550, 526, 520, 622, 562, 778, 646, 652, 856, 946, 688, 940, 1000, 1024, 1066, 1012, 1168, 1126, 1456, 1276, 1108, 1252, 1234, 1558, 1390, 1420
Offset: 1

Views

Author

Matt Westwood, Apr 09 2020

Keywords

References

  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers (Revised Edition), Penguin Books, 1997, p. 95.

Crossrefs

Cf. A000959 (lucky numbers).

Extensions

More terms from Giovanni Resta, Apr 09 2020

A285586 Complete list of numbers n for which there exists no prime number between n and 9n/8 inclusive.

Original entry on oeis.org

1, 4, 6, 8, 9, 14, 15, 20, 24, 25, 32
Offset: 1

Views

Author

Matt Westwood, Apr 22 2017

Keywords

References

  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers (Revised Edition), Penguin Books, 1997, page 106.

Links

  • Prime Curios! 48

A284987 Juggler sequence starting at 37.

Original entry on oeis.org

37, 225, 3375, 196069, 86818724, 9317, 899319, 852846071, 24906114455136, 4990602, 2233, 105519, 34276462, 5854, 76, 8, 2, 1
Offset: 0

Views

Author

Matt Westwood, Apr 07 2017

Keywords

Comments

Many sources state that the Juggler sequence on 37 is, for example, "the first tall peak in its graph", and "the high water number of steps are" and so on, without specifically giving the actual sequence. As this specific instance is cited in various places as a specific instance, if not a special case, it seems worthy to document it here explicitly.

References

  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Revised Edition, Penguin Books, 1997, page 99.

Links

Crossrefs

Cf. A007320, A094670, A094683.

Programs

  • PARI
    Juggler(n)={my(L=List([n])); while(n<>1, n=sqrtint(n^(2-(-1)^n)); listput(L,n)); Vec(L)}
{ Juggler(37) } \\ Andrew Howroyd, Apr 27 2020

Formula

a(0) = 37, a(n) = floor(sqrt(a(n-1))): n even, a(n) = floor((sqrt(a(n-1)))^3): n odd.

A277438 Numbers whose letters are in alphabetical order when spelled in French.

Original entry on oeis.org

2, 5, 10, 100
Offset: 1

Views

Author

Matt Westwood, Oct 15 2016

Keywords

Comments

40 (forty) is the only number with this property in English.
1 (un) is the only number with the reverse property in French. - Michel Marcus, Nov 13 2016
1 (one) is the only number with the reverse property in English. - Matt Westwood, Feb 25 2017

Examples

			The names in French for a(1)..a(4) are: deux, cinq, dix, cent.

References

  • D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, p. 101.

A175882 Number of groupoids of order n with no identity element.

Original entry on oeis.org

1, 0, 12, 19440, 4293918720, 298022460937500000, 10314424627908807366593740800, 256923577502496762167593902921782457650400, 6277101735385253516143083463326608130132905949327651766272, 196627050475552807506414708879663572595247698231546775823411085055396409324160
Offset: 0

Views

Author

Matt Westwood, Dec 05 2010

Keywords

Links

Crossrefs

Cf. A002489, A090602.

Programs

  • PARI
    a(n) = n^(n^2) - n^(((n-1)^2)+1) \\ Andrew Howroyd, Jan 23 2022

Formula

a(n) = n^(n^2) - n^(((n-1)^2)+1) = A002489(n) - A090602(n).

Extensions

a(0)=1 prepended and terms a(7) and beyond from Andrew Howroyd, Jan 23 2022

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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