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.

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A074507 a(n) = 1^n + 3^n + 5^n.

Original entry on oeis.org

3, 9, 35, 153, 707, 3369, 16355, 80313, 397187, 1972809, 9824675, 49005273, 244672067, 1222297449, 6108298595, 30531927033, 152630937347, 763068593289, 3815084686115, 19074648589593, 95370918425027, 476847618556329
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Table[1^n + 3^n + 5^n, {n, 0, 22}]
    LinearRecurrence[{9,-23,15},{3,9,35},30] (* Harvey P. Dale, Mar 02 2022 *)
  • PARI
    a(n) = 1 + 3^n + 5^n; \\ Michel Marcus, Aug 07 2017

Formula

a(n) = 8*a(n-1) - 15*a(n-2) + 8.
G.f.: 1/(1-x)+1/(1-3*x)+1/(1-5*x). E.g.f.: e^x+e^(3*x)+e^(5*x). [Mohammad K. Azarian, Dec 26 2008]

A155589 a(n) = 6^n + 2^n - 1.

Original entry on oeis.org

1, 7, 39, 223, 1311, 7807, 46719, 280063, 1679871, 10078207, 60467199, 362799103, 2176786431, 13060702207, 78364180479, 470185017343, 2821109972991, 16926659575807, 101559956930559, 609359740534783, 3656158441111551, 21936950642475007, 131621703846461439
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 24 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-6*x)+1/(1-2*x)-1/(1-x).
E.g.f.: exp(6*x)+exp(2*x)-exp(x).
a(n) = 8*a(n-1)-12*a(n-2)-5 with a(0) = 1, a(1) = 7. - Vincenzo Librandi, Jul 21 2010

A074528 a(n) = 2^n + 3^n + 6^n.

Original entry on oeis.org

3, 11, 49, 251, 1393, 8051, 47449, 282251, 1686433, 10097891, 60526249, 362976251, 2177317873, 13062296531, 78368963449, 470199366251, 2821153019713, 16926788715971, 101560344351049, 609360902796251
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Comments

From Álvar Ibeas, Mar 24 2015: (Start)
Number of isomorphism classes of 3-fold coverings of a connected graph with circuit rank n+1 [Kwak and Lee].
Number of orbits of the conjugacy action of Sym(3) on Sym(3)^(n+1) [Kwak and Lee, 2001].
(End)

References

  • J. H. Kwak and J. Lee, Enumeration of graph coverings, surface branched coverings and related group theory, in Combinatorial and Computational Mathematics (Pohang, 2000), ed. S. Hong et al., World Scientific, Singapore 2001, pp. 97-161. [Added by N. J. A. Sloane, Nov 12 2009]

Crossrefs

A246985 is essentially identical.
Third row of A160449, shifted.

Programs

Formula

From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-2*x)+1/(1-3*x)+1/(1-6*x).
E.g.f.: exp(2*x) + exp(3*x) + exp(6*x). (End)
a(n) = 11*a(n-1) - 36*a(n-2) + 36*a(n-3). - Wesley Ivan Hurt, Aug 21 2020

A155595 11^n+2^n-1.

Original entry on oeis.org

1, 12, 124, 1338, 14656, 161082, 1771624, 19487298, 214359136, 2357948202, 25937425624, 285311672658, 3138428380816, 34522712152122, 379749833599624, 4177248169448418, 45949729863637696, 505447028499424842
Offset: 0

Views

Author

Mohammad K. Azarian, Jan 24 2009

Keywords

Crossrefs

Programs

Formula

G.f.: 1/(1-11*x)+1/(1-2*x)-1/(1-x). E.g.f.: e^(11*x)+e^(2*x)-e^x.
a(n)=13*a(n-1)-22*a(n-2)-10 with a(0)=1, a(1)=12 - Vincenzo Librandi, Jul 21 2010

A074506 a(n) = 1^n + 3^n + 4^n.

Original entry on oeis.org

3, 8, 26, 92, 338, 1268, 4826, 18572, 72098, 281828, 1107626, 4371452, 17308658, 68703188, 273218426, 1088090732, 4338014018, 17309009348, 69106897226, 276040168412, 1102998412178, 4408506864308, 17623567104026
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Table[1^n + 3^n + 4^n, {n, 0, 22}]
    LinearRecurrence[{8,-19,12},{3,8,26},30] (* Harvey P. Dale, May 12 2025 *)

Formula

a(n) = 7*a(n-1) - 12*a(n-2) + 6 with a(0)=3, a(1)=8. - Vincenzo Librandi, Jul 19 2010
a(n) = 8*a(n-1) - 19*a(n-2) + 12*a(n-3). - R. J. Mathar, Jul 18 2010
From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-x) + 1/(1-3*x) + 1/(1-4*x).
E.g.f.: e^x + e^(3*x) + e^(4*x). (End)

A074526 a(n) = 2^n + 3^n + 4^n.

Original entry on oeis.org

3, 9, 29, 99, 353, 1299, 4889, 18699, 72353, 282339, 1108649, 4373499, 17312753, 68711379, 273234809, 1088123499, 4338079553, 17309140419, 69107159369, 276040692699, 1102999460753, 4408508961459, 17623571298329
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Crossrefs

Programs

  • Magma
    [2^n + 3^n + 4^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
  • Mathematica
    Table[2^n + 3^n + 4^n, {n, 0, 23}]
    LinearRecurrence[{9,-26,24},{3,9,29},30] (* Harvey P. Dale, Jun 14 2022 *)

Formula

From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-2*x)+1/(1-3*x)+1/(1-4*x).
E.g.f.: exp(2*x)+exp(3*x)+exp(4*x). (End)

A074502 a(n) = 1^n + 2^n + 6^n.

Original entry on oeis.org

3, 9, 41, 225, 1313, 7809, 46721, 280065, 1679873, 10078209, 60467201, 362799105, 2176786433, 13060702209, 78364180481, 470185017345, 2821109972993, 16926659575809, 101559956930561, 609359740534785, 3656158441111553
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Comments

From Jonathan Vos Post, Apr 16 2005: (Start)
Primes in this sequence include: a(2) = 41, a(10) = 60467201, a(18) = 101559956930561, a(34) = 286511799958070449017978881, a(58) = 1357602166130257152481187563448636039086735361.
Semiprimes in this sequence include: a(1) = 9 = 3^2, a(4) = 1313 = 13 * 101, a(6) = 46721 = 19 * 2459, a(8) = 1679873 = 13 * 129221, a(12) = 2176786433 = 19 * 114567707, a(13) = 13060702209 = 3 * 4353567403, a(28) = 6140942214465083932673 = 13 * 472380170343467994821, a(29) = 36845653286789429854209 = 3 * 12281884428929809951403, a(72) = 106387358923716524807713475752456398462534338499504504833 = 59670762632990981 * 1782905969847563299479030657520813855693. (End)

Crossrefs

Programs

  • Mathematica
    Table[1^n + 2^n + 6^n, {n, 0, 20}]
    LinearRecurrence[{9,-20,12},{3,9,41},30] (* Harvey P. Dale, Aug 15 2017 *)

Formula

G.f.: 1/(1-x)+1/(1-2*x)+1/(1-6*x). E.g.f.: e^x+e^(2*x)+e^(6*x). [Mohammad K. Azarian, Dec 26 2008]
a(n) = 8*a(n-1) - 12*a(n-2) + 5, n> 1. [Gary Detlefs, Jun 21 2010]

A074515 a(n) = 1^n + 4^n + 9^n.

Original entry on oeis.org

3, 14, 98, 794, 6818, 60074, 535538, 4799354, 43112258, 387682634, 3487832978, 31385253914, 282446313698, 2541932937194, 22877060890418, 205892205836474, 1853024483819138, 16677198879535754, 150094704016475858
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Table[1^n + 4^n + 9^n, {n, 0, 20}]
    LinearRecurrence[{14,-49,36},{3,14,98},30] (* Harvey P. Dale, Aug 06 2013 *)
  • Python
    def a(n): return 1 + 4**n + 9**n
    print([a(n) for n in range(19)]) # Michael S. Branicky, Mar 14 2021

Formula

From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-x) + 1/(1-4*x) + 1/(1-9*x).
E.g.f.: e^x + e^(4*x) + e^(9*x). (End)
a(n) = 13*a(n-1) - 36*a(n-2) + 24 with a(0)=3, a(1)=14. - Vincenzo Librandi, Jul 21 2010

A074535 a(n) = 2^n + 4^n + 8^n.

Original entry on oeis.org

3, 14, 84, 584, 4368, 33824, 266304, 2113664, 16843008, 134480384, 1074791424, 8594130944, 68736258048, 549822930944, 4398314962944, 35185445863424, 281479271743488, 2251816993685504, 18014467229220864, 144115462954287104
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Comments

Number of monic irreducible polynomials of degree 1 in GF(2^n)[x,y,z]. - Max Alekseyev, Jan 23 2006

Crossrefs

Programs

  • Magma
    [2^n + 4^n + 8^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
    
  • Mathematica
    Table[2^n + 4^n + 8^n, {n, 0, 20}]
  • Python
    def a(n): return 2**n + 4**n + 8**n
    print([a(n) for n in range(20)]) # Michael S. Branicky, Mar 14 2021

Formula

G.f.: 1/(1-2*x)+1/(1-4*x)+1/(1-8*x). E.g.f.: exp(2*x)+exp(4*x)+exp(8*x). [Mohammad K. Azarian, Dec 26 2008]
Let A=[1, 1, 1;2, 0, -2;1, -1, 1], the 3 X 3 Krawtchouk matrix. Then a(n)=trace((A*A')^n). - Paul Barry, Sep 18 2004

A074579 a(n) = 6^n + 8^n + 9^n.

Original entry on oeis.org

3, 23, 181, 1457, 11953, 99593, 840241, 7160057, 61503553, 531715913, 4620992401, 40333791257, 353325795553, 3104682336233, 27353203130161, 241545689168057, 2137316275469953, 18945908172796553, 168210593763149521
Offset: 0

Views

Author

Robert G. Wilson v, Aug 23 2002

Keywords

Crossrefs

Programs

  • Magma
    [6^n + 8^n + 9^n: n in [0..20]]; // Vincenzo Librandi, May 20 2011
  • Mathematica
    Table[6^n + 8^n + 9^n, {n, 0, 20}]
    LinearRecurrence[{23,-174,432},{3,23,181},30] (* Harvey P. Dale, Sep 20 2016 *)

Formula

From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-6*x) + 1/(1-8*x) + 1/(1-9*x).
E.g.f.: e^(6*x) + e^(8*x) + e^(9*x). (End)
a(n) = 23*a(n-1)-174*a(n-2)+432*a(n-3). - Wesley Ivan Hurt, Apr 17 2022
Previous Showing 21-30 of 99 results. Next