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 1-5 of 5 results.

A000503 a(n) = floor(tan(n)).

Original entry on oeis.org

0, 1, -3, -1, 1, -4, -1, 0, -7, -1, 0, -226, -1, 0, 7, -1, 0, 3, -2, 0, 2, -2, 0, 1, -3, -1, 1, -4, -1, 0, -7, -1, 0, -76, -1, 0, 7, -1, 0, 3, -2, 0, 2, -2, 0, 1, -3, -1, 1, -4, -1, 0, -7, -1, 0, -46, -1, 0, 8, -1, 0, 3, -2, 0, 2, -2, 0, 1, -3, -1, 1, -4, -1, 0, -6, -1, 0, -33, -1, 0, 9, -1, 0, 3, -2, 0, 2, -2, 0, 1, -2, -1, 1, -3, -1, 0, -6, -1, 0, -26
Offset: 0

Views

Author

Keywords

Comments

Every integer appears infinitely often. - Charles R Greathouse IV, Aug 06 2012
Does not satisfy Benford's law [Whyman et al., 2016]. - N. J. A. Sloane, Feb 12 2017

Crossrefs

Programs

Extensions

More terms from Stefan Steinerberger, Apr 09 2006

A293751 Values of positive integer i such that floor(tan(-i)) = 1.

Original entry on oeis.org

18, 21, 40, 43, 62, 65, 84, 87, 90, 106, 109, 112, 128, 131, 134, 150, 153, 156, 172, 175, 178, 197, 200, 219, 222, 241, 244, 263, 266, 285, 288, 307, 310, 329, 332, 351, 354, 373, 376, 395, 398, 417, 420, 439, 442, 445, 461, 464, 467, 483, 486, 489, 505, 508, 511, 527, 530, 533, 552, 555, 574, 577, 596
Offset: 1

Views

Author

V.J. Pohjola, Oct 15 2017

Keywords

Crossrefs

Cf. A000530, A293698, A293699, A293702, A293705, A293700, A293701, A293704. a(n) are also the roots of A195910(i)=1, starting from i=1.

Programs

  • Mathematica
    rootsn = Flatten[Position[Table[Floor[Tan[-i]], {i, 1, 10^3}], 1]];
    (*a(n) = rootsn[[n]]*)
    Select[Range@600, Floor@Tan@-# == 1 &] (* Robert G. Wilson v, Nov 19 2017 *)
  • PARI
    isok(n) = floor(tan(-n)) == 1; \\ Michel Marcus, Nov 03 2017

Formula

floor(tan(-n)) = -ceiling(tan(n)).

A037448 a(n) = floor(cot(n)).

Original entry on oeis.org

0, -1, -8, 0, -1, -4, 1, -1, -3, 1, -1, -2, 2, 0, -2, 3, 0, -1, 6, 0, -1, 112, 0, -1, -8, 0, -1, -4, 1, -1, -3, 1, -1, -2, 2, 0, -2, 3, 0, -1, 6, 0, -1, 56, 0, -1, -9, 0, -1, -4, 1, -1, -3, 1, -1, -2, 2, 0, -2, 3, 0, -1, 5, 0, -1, 37, 0, -1, -9, 0, -1, -4, 1, -1, -3, 1, -1, -2, 2, 0, -2, 3, 0, -1, 5, 0, -1, 28, 0, -1, -10, 0, -1, -4, 1, -1, -3
Offset: 1

Views

Author

Jason Earls, Jun 30 2001

Keywords

Comments

Contains all integers infinitely often. - Charles R Greathouse IV, Aug 06 2012

Crossrefs

Programs

  • Magma
    [Floor(Cot(n)): n in [1..100]]; // Vincenzo Librandi, Jun 15 2015
  • Mathematica
    Floor[Cot[Range[100]]] (* Harvey P. Dale, Dec 26 2024 *)
  • PARI
    v=[]; for(n=1,260,v=concat(v,floor(cotan(n)))); v
    

Extensions

a(44) corrected by T. D. Noe, Jan 21 2008

A195911 a(n) = ceiling(cot(n)).

Original entry on oeis.org

1, 0, -7, 1, 0, -3, 2, 0, -2, 2, 0, -1, 3, 1, -1, 4, 1, 0, 7, 1, 0, 113, 1, 0, -7, 1, 0, -3, 2, 0, -2, 2, 0, -1, 3, 1, -1, 4, 1, 0, 7, 1, 0, 57, 1, 0, -8, 1, 0, -3, 2, 0, -2, 2, 0, -1, 3, 1, -1, 4, 1, 0, 6, 1, 0, 38, 1, 0, -8, 1, 0, -3, 2, 0, -2, 2, 0, -1, 3
Offset: 1

Views

Author

Mohammad K. Azarian, Mar 15 2012

Keywords

Crossrefs

Programs

A005699 a(n) = ceiling(tan(n)^2).

Original entry on oeis.org

0, 3, 5, 1, 2, 12, 1, 1, 47, 1, 1, 51054, 1, 1, 53, 1, 1, 13, 2, 1, 6, 3, 1, 3, 5, 1, 2, 11, 1, 1, 42, 1, 1, 5673, 1, 1, 61, 1, 1, 14, 2, 1, 6, 3, 1, 3, 5, 1, 2, 11, 1, 1, 37, 1, 1, 2042, 1, 1, 70, 1, 1, 15, 2, 1, 6, 3, 1, 3, 5, 1, 2, 10, 1, 1, 33, 1, 1, 1042, 1, 1, 82, 1, 1, 16, 2, 1, 6, 3, 1, 3, 4, 1, 2, 9, 1, 1, 30, 1, 1, 630, 1, 1, 96, 1, 1, 17
Offset: 0

Views

Author

Keywords

Comments

For n > 0, a(n) = floor(sec(n)^2). - N. J. A. Sloane, Mar 17 2025

Crossrefs

Programs

Extensions

More terms from Seiichi Manyama, Feb 28 2024
Showing 1-5 of 5 results.