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 1-4 of 4 results.

A017305 a(n) = 10*n + 3.

Original entry on oeis.org

3, 13, 23, 33, 43, 53, 63, 73, 83, 93, 103, 113, 123, 133, 143, 153, 163, 173, 183, 193, 203, 213, 223, 233, 243, 253, 263, 273, 283, 293, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 403, 413, 423, 433, 443, 453, 463, 473, 483, 493, 503, 513, 523, 533
Offset: 0

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Author

Keywords

Comments

Apart from initial term(s), dimension of the space of weight 2n cusp forms for Gamma_0(38).

Crossrefs

Programs

Formula

a(n) = A017198(n) - A156677(n+2). - Reinhard Zumkeller, Jul 13 2010
a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, May 28 2011
G.f.: (3+7*x)/(x-1)^2. - R. J. Mathar, Apr 11 2016
E.g.f.: exp(x)*(3 + 10*x). - Stefano Spezia, Aug 22 2023
a(n) = A016885(2*n). - Elmo R. Oliveira, Apr 10 2025

A017198 a(n) = (9*n + 3)^2.

Original entry on oeis.org

9, 144, 441, 900, 1521, 2304, 3249, 4356, 5625, 7056, 8649, 10404, 12321, 14400, 16641, 19044, 21609, 24336, 27225, 30276, 33489, 36864, 40401, 44100, 47961, 51984, 56169, 60516, 65025, 69696
Offset: 0

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Author

Keywords

Comments

a(n) = A000290(A017197(n)) = A156677(n+2) + A017305(n). - Reinhard Zumkeller, Jul 13 2010

Programs

Formula

a(0)=9, a(1)=144, a(2)=441, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, Dec 25 2015
G.f.: (-9 - 117*x - 36*x^2) / (x-1)^3. - R. J. Mathar, Jul 14 2016

A156771 a(n) = 729*n - 531.

Original entry on oeis.org

198, 927, 1656, 2385, 3114, 3843, 4572, 5301, 6030, 6759, 7488, 8217, 8946, 9675, 10404, 11133, 11862, 12591, 13320, 14049, 14778, 15507, 16236, 16965, 17694, 18423, 19152, 19881, 20610, 21339, 22068, 22797, 23526, 24255, 24984, 25713
Offset: 1

Views

Author

Vincenzo Librandi, Feb 15 2009

Keywords

Comments

The identity (6561*n^2 - 9558*n + 3482)^2 - (81*n^2 - 118*n + 43)*(729*n - 531)^2 = 1 can be written as A156773(n)^2 - A156677(n)*a(n)^2 = 1.

Crossrefs

Programs

  • Magma
    I:=[198, 927]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
    
  • Mathematica
    LinearRecurrence[{2,-1},{198,927},40]
  • PARI
    a(n)=729*n-531 \\ Charles R Greathouse IV, Dec 23 2011
    
  • Sage
    [9*(81*n -59) for n in [1..50]] # G. C. Greubel, Jun 19 2021

Formula

a(n) = 2*a(n-1) - a(n-2).
G.f.: x*(198 + 531*x)/(1-x)^2.
E.g.f.: 9*(59 - (59 - 81*x)*exp(x)). - G. C. Greubel, Jun 19 2021

A156773 a(n) = 6561*n^2 - 9558*n + 3482.

Original entry on oeis.org

3482, 485, 10610, 33857, 70226, 119717, 182330, 258065, 346922, 448901, 564002, 692225, 833570, 988037, 1155626, 1336337, 1530170, 1737125, 1957202, 2190401, 2436722, 2696165, 2968730, 3254417, 3553226, 3865157, 4190210, 4528385
Offset: 0

Views

Author

Vincenzo Librandi, Feb 15 2009

Keywords

Comments

The identity (6561*n^2 - 9558*n + 3482)^2 - (81*n^2 - 118*n + 43)*(729*n - 531)^2 = 1 can be written as a(n)^2 - A156677(n)*A156771(n)^2 = 1 for n>0. [rewritten by Bruno Berselli, Jul 21 2011]

Crossrefs

Programs

  • Magma
    [6561*n^2-9558*n+3482: n in [0..35]];
    
  • Mathematica
    Table[6561n^2-9558n+3482,{n,0,30}] (* Harvey P. Dale, Apr 06 2011 *)
  • PARI
    a(n)=6561*n^2-9558*n+3482 \\ Charles R Greathouse IV, Dec 23 2011
    
  • Sage
    [3482 -9558*n +6561*n^2 for n in (0..35)] # G. C. Greubel, Jun 21 2021

Formula

G.f.: (3482 - 9961*x + 19601*x^2)/(1-x)^3. - Colin Barker, Jan 09 2012
E.g.f.: (3482 - 2997*x + 6561*x^2)*exp(x). - G. C. Greubel, Jun 21 2021
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Wesley Ivan Hurt, Sep 03 2022

Extensions

Checked by Michael B. Porter, Jun 16 2010
Offset corrected by N. J. A. Sloane, Jun 22 2010
Showing 1-4 of 4 results.