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.

A008606 Multiples of 24.

Original entry on oeis.org

0, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264, 288, 312, 336, 360, 384, 408, 432, 456, 480, 504, 528, 552, 576, 600, 624, 648, 672, 696, 720, 744, 768, 792, 816, 840, 864, 888, 912, 936, 960, 984, 1008, 1032, 1056, 1080, 1104, 1128, 1152, 1176, 1200
Offset: 0

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Author

Keywords

Comments

If n is a multiple of 24, also the sum of the divisors of n-1 is a multiple of 24. - Vincenzo Librandi, Apr 12 2014
This is the sequence of numbers n such that A259748(n)/n = 11/12. - Danny Rorabaugh, Oct 22 2015

Crossrefs

Programs

Formula

G.f.: 24*x/(1-x)^2. - Vincenzo Librandi, Jun 11 2013
a(n) = 24*A001477(n) - Danny Rorabaugh, Oct 24 2015
E.g.f.: 24*x*exp(x). - Stefano Spezia, Mar 02 2025

A008607 Multiples of 25.

Original entry on oeis.org

0, 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600, 625, 650, 675, 700, 725, 750, 775, 800, 825, 850, 875, 900, 925, 950, 975, 1000, 1025, 1050, 1075, 1100, 1125, 1150, 1175, 1200, 1225
Offset: 0

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Author

Keywords

Crossrefs

Programs

Formula

G.f.: 25*x/(1-x)^2. - Colin Barker, Feb 19 2012
From Wesley Ivan Hurt, May 19 2024: (Start)
a(n) = 25*n.
a(n) = 2*a(n-1) - a(n-2). (End)
E.g.f.: 25*x*exp(x). - Stefano Spezia, Oct 18 2024

A195819 Multiples of 29.

Original entry on oeis.org

0, 29, 58, 87, 116, 145, 174, 203, 232, 261, 290, 319, 348, 377, 406, 435, 464, 493, 522, 551, 580, 609, 638, 667, 696, 725, 754, 783, 812, 841, 870, 899, 928, 957, 986, 1015, 1044, 1073, 1102, 1131, 1160, 1189, 1218, 1247, 1276, 1305, 1334
Offset: 0

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Author

Omar E. Pol, Oct 12 2011

Keywords

Comments

Length of hypotenuses on the main diagonal of the Pythagorean spiral whose edges have length A195033 and whose vertices are the numbers A195034, if n >= 1.

Crossrefs

Programs

Formula

a(n) = 29*n.
From Elmo R. Oliveira, Mar 21 2024: (Start)
G.f.: 29*x/(x-1)^2.
E.g.f.: 29*x*exp(x).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A244632 a(n) = 23*n^2.

Original entry on oeis.org

0, 23, 92, 207, 368, 575, 828, 1127, 1472, 1863, 2300, 2783, 3312, 3887, 4508, 5175, 5888, 6647, 7452, 8303, 9200, 10143, 11132, 12167, 13248, 14375, 15548, 16767, 18032, 19343, 20700, 22103, 23552, 25047, 26588, 28175, 29808, 31487, 33212, 34983, 36800, 38663
Offset: 0

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Author

Vincenzo Librandi, Jul 03 2014

Keywords

Comments

First bisection of A195058. - Bruno Berselli, Jul 03 2014

Crossrefs

Cf. similar sequences listed in A244630.

Programs

  • Magma
    [23*n^2: n in [0..40]];
    
  • Mathematica
    Table[23 n^2, {n, 0, 40}]
    LinearRecurrence[{3,-3,1},{0,23,92},50] (* Harvey P. Dale, Jul 14 2024 *)
  • PARI
    a(n)=23*n^2 \\ Charles R Greathouse IV, Jun 17 2017

Formula

G.f.: 23*x*(1 + x)/(1 - x)^3. [corrected by Bruno Berselli, Jul 03 2014]
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2.
a(n) = 23*A000290(n). - Omar E. Pol, Jul 03 2014
From Elmo R. Oliveira, Dec 01 2024: (Start)
E.g.f.: 23*x*(1 + x)*exp(x).
a(n) = n*A008605(n) = A195058(2*n). (End)

A317323 Multiples of 23 and odd numbers interleaved.

Original entry on oeis.org

0, 1, 23, 3, 46, 5, 69, 7, 92, 9, 115, 11, 138, 13, 161, 15, 184, 17, 207, 19, 230, 21, 253, 23, 276, 25, 299, 27, 322, 29, 345, 31, 368, 33, 391, 35, 414, 37, 437, 39, 460, 41, 483, 43, 506, 45, 529, 47, 552, 49, 575, 51, 598, 53, 621, 55, 644, 57, 667, 59, 690, 61, 713, 63, 736, 65, 759, 67, 782, 69
Offset: 0

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Author

Omar E. Pol, Jul 25 2018

Keywords

Comments

Partial sums give the generalized 27-gonal numbers (A316725).
a(n) is also the length of the n-th line segment of the rectangular spiral whose vertices are the generalized 27-gonal numbers.

Crossrefs

Cf. A008605 and A005408 interleaved.
Column 23 of A195151.
Sequences whose partial sums give the generalized k-gonal numbers: A026741 (k=5), A001477 (k=6), zero together with A080512 (k=7), A022998 (k=8), A195140 (k=9), zero together with A165998 (k=10), A195159 (k=11), A195161 (k=12), A195312 (k=13), A195817 (k=14).
Cf. A316725.

Programs

  • Mathematica
    With[{nn=40},Riffle[23*Range[0,nn],Range[1,2*nn,2]]] (* or *) LinearRecurrence[{0,2,0,-1},{0,1,23,3},80] (* Harvey P. Dale, May 05 2019 *)
  • PARI
    concat(0, Vec(x*(1 + 23*x + x^2) / ((1 - x)^2*(1 + x)^2) + O(x^60))) \\ Colin Barker, Jul 29 2018

Formula

a(2n) = 23*n, a(2n+1) = 2*n + 1.
From Colin Barker, Jul 29 2018: (Start)
G.f.: x*(1 + 23*x + x^2) / ((1 - x)^2*(1 + x)^2).
a(n) = 2*a(n-2) - a(n-4) for n>3. (End)
Multiplicative with a(2^e) = 23*2^(e-1), and a(p^e) = p^e for an odd prime p. - Amiram Eldar, Oct 14 2023
Dirichlet g.f.: zeta(s-1) * (1 + 21/2^s). - Amiram Eldar, Oct 26 2023
Showing 1-5 of 5 results.