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 1-10 of 50 results. Next

A152128 Duplicate of A115457.

Original entry on oeis.org

0, 6, 35, 694, 26089, 1862994, 253247715, 66799608630, 34698378752226, 35781375988234520, 73534241823793715433
Offset: 0

Views

Author

Jonathan Vos Post, Nov 25 2008

Keywords

Comments

This is from Hou and Mullen, p.29, Table 1: I_2(n), q = 2.

Crossrefs

Formula

Apparently a(n)=A115457(n), n>0. [R. J. Mathar, Dec 03 2008]

A115505 Number of monic irreducible polynomials of degree 2 in GF(2^n)[x1,x2,x3,x4,x5].

Original entry on oeis.org

2095135, 1466014571406, 1317624575992306876, 1289520874254978952587000, 1308542555074300717818898758640, 1350326852860866917910548456417128416, 1404771351088543190017398373020865731215296
Offset: 1

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

A122743 Number of normalized polynomials of degree n in GF(2)[x,y].

Original entry on oeis.org

1, 6, 56, 960, 31744, 2064384, 266338304, 68451041280, 35115652612096, 35993612646875136, 73750947497819242496, 302157667927362455470080, 2475577847115856892504571904, 40562343327224770087344704323584, 1329187430965708569562959165777772544
Offset: 0

Views

Author

N. J. A. Sloane, Aug 13 2008

Keywords

Comments

a(n) = n-th elementary symmetric function in n+1 variables evaluated at {2,4,8,16,...,2^(n+1)}; see Mathematica program.
a(n) is the number of simple labeled graphs on {1,2,...,n+2} such that the vertex 1 is not isolated. - Geoffrey Critzer, Sep 12 2013
a(n) is the HANKEL transform of the large Schröder numbers A006318(n+2). - Emanuele Munarini, Sep 14 2017

Examples

			Let esp abbreviate "elementary symmetric polynomial".  Then
0th esp of {2} is 1.
1st esp of {2,4} is 2+4 = 6.
2nd esp of {2,4,8} is 2*4 + 2*8 + 4*8 = 56.
		

References

  • Joachim von zur Gathen, Alfredo Viola, and Konstantin Ziegler, Counting reducible, powerful, and relatively irreducible multivariate polynomials over finite fields, in: A. López-Ortiz (Ed.), LATIN 2010: Theoretical Informatics, Proceedings of the 9th Latin American Symposium, Oaxaca, Mexico, April 19-23, 2010, in: Lecture Notes in Comput. Sci., vol. 6034, Springer, Berlin, Heidelberg, 2010, pp. 243-254 (Extended Abstract). Final version to appear in SIAM J. Discrete Math.

Crossrefs

Row sums of powers of two triangles A000079.
Equals A000225(n+1)*2^A000217(n).

Programs

  • Magma
    [2^((n+1)*(n+2) div 2) - 2^(n*(n+1) div 2): n in [0..30]]; // Vincenzo Librandi, Oct 01 2015
  • Maple
    seq(2^((n*(1+n))/2)*(2^(1+n)-1), n=0..14); # Peter Luschny, Sep 19 2017
  • Mathematica
    f[k_] := 2^k; t[n_] := Table[f[k], {k, 1, n}]
    a[n_] := SymmetricPolynomial[n - 1, t[n]]
    Table[a[n], {n, 1, 16}] (* A122743 *)
    (* Clark Kimberling, Dec 29 2011 *)
  • PARI
    a(n) = 2^((n+1)*(n+2)/2) - 2^(n*(n+1)/2);
    vector (100, n, a(n-1)) \\ Altug Alkan, Sep 30 2015
    

Formula

a(n) = 2^((n+1)(n+2)/2) - 2^(n(n+1)/2). - Paul D. Hanna, Apr 08 2009
E.g.f.: d(G(2x)-G(x))/dx where G(x) is the e.g.f. for A006125. - Geoffrey Critzer, Sep 12 2013
From Emanuele Munarini, Sep 14 2017: (Start)
(2^(n+1)-1)*a(n+1) - 2^(n+1)*(2^(n+2)-1)*a(n) = 0.
a(n+1) - (2^(n+2)+1)*a(n) = 2^(binomial(n+1,2)).
a(n+2) - (5*2^(n+1)+1)*a(n+1) + 2^(n+1)*(2^(n+2)+1)*a(n) = 0. (End)

Extensions

Edited, terms and links added by Johannes W. Meijer, Oct 10 2010
Comments corrected, reference added, and example edited by Konstantin Ziegler, Dec 04 2012
a(14) from Vincenzo Librandi, Oct 01 2015

A115490 Number of monic irreducible polynomials of degree 4 in GF(2^n)[x].

Original entry on oeis.org

3, 60, 1008, 16320, 261888, 4193280, 67104768, 1073725440, 17179803648, 274877644800, 4398045462528, 70368739983360, 1125899890065408, 18014398442373120, 288230375883276288, 4611686017353646080, 73786976290543239168, 1180591620700231434240, 18889465931409861378048
Offset: 1

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

Programs

  • Magma
    [(16^n-4^n)/4: n in [1..20]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    CoefficientList[Series[3/((16 x - 1) (4 x - 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Jul 25 2014 *)

Formula

a(0)=0, a(1)=3; for n>1, a(n) = 20*a(n-1)-64*a(n-2). - T. D. Noe, Nov 30 2006
G.f.: 3*x / ( (16*x-1)*(4*x-1) ). - R. J. Mathar, Jul 23 2014
a(n) = (16^n-4^n)/4. - Vincenzo Librandi, Jul 25 2014
E.g.f.: exp(4*x)*(exp(12*x) - 1)/4. - Stefano Spezia, Aug 16 2024

A115478 Number of monic irreducible polynomials of degree 3 in GF(3)[x1,...,xn].

Original entry on oeis.org

8, 25520, 1742232560, 25015771681981520, 261673816513678364838549056, 5986257591281009894301357511191882167288, 898505149957215605206589914754802519619582611893609512640
Offset: 1

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

A115489 Number of monic irreducible polynomials of degree 3 in GF(2^n)[x].

Original entry on oeis.org

2, 20, 168, 1360, 10912, 87360, 699008, 5592320, 44739072, 357913600, 2863310848, 22906490880, 183251935232, 1466015498240, 11728124018688, 93824992215040, 750599937851392, 6004799503073280, 48038396025110528
Offset: 1

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

Programs

  • Magma
    [-(1/3)*2^n+(1/3)*8^n: n in [1..20]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    LinearRecurrence[{10,-16},{2,20},30] (* Harvey P. Dale, Sep 25 2013 *)
    CoefficientList[Series[2/((8 x - 1) (2 x - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 25 2014 *)

Formula

a(0)=0, a(1)=2, a(n)=10a(n-1)-16a(n-2). - T. D. Noe, Nov 30 2006
G.f.: 2*x / ( (8*x-1)*(2*x-1) ). - R. J. Mathar, Jul 23 2014

A115504 Number of monic irreducible polynomials of degree 1 in GF(2^n)[x1,x2,x3,x4,x5].

Original entry on oeis.org

62, 1364, 37448, 1118480, 34636832, 1090785344, 34630287488, 1103823438080, 35253226045952, 1127000493261824, 36046397799139328, 1153203048319815680, 36897992296869404672, 1180663682709764194304
Offset: 1

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

Programs

  • Magma
    [2^n+4^n+8^n+16^n+32^n: n in [1..20]]; // Vincenzo Librandi, Jul 25 2014
  • Mathematica
    CoefficientList[Series[-2 (31 - 1240 x + 14880 x^2 - 63488 x^3 + 81920 x^4)/((4 x - 1) (2 x - 1) (8 x - 1) (16 x - 1) (32 x - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 25 2014 *)
    LinearRecurrence[{62,-1240,9920,-31744,32768},{62,1364,37448,1118480,34636832},20] (* Harvey P. Dale, Oct 07 2019 *)

Formula

a(n) = A034665(n) - 1, or a(n) = 2^n + 4^n + 8^n + 16^n + 32^n. - Chris Boyd, Apr 26 2014
G.f.: -2*x*( 31-1240*x+14880*x^2-63488*x^3+81920*x^4 ) / ( (4*x-1)*(2*x-1)*(8*x-1)*(16*x-1)*(32*x-1) ). - R. J. Mathar, Jul 23 2014

A115458 Number of monic irreducible polynomials of degree n in GF(2)[x,y,z].

Original entry on oeis.org

1, 14, 903, 1034350, 34343703541, 72057077817486762, 19342812032942216095260047, 1329227995494773618659262698956301950, 46768052394568954962565705269783921192917309706498
Offset: 0

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

A115461 Number of monic irreducible polynomials of degree n in GF(3)[x,y].

Original entry on oeis.org

1, 12, 273, 25520, 6778629, 5132148528, 11368775698280, 74897449398451680, 1476178370884382958936, 87205387550224830516286800, 15450442981642705273095610563240, 8211400746584626963688710296061894800
Offset: 0

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

A115465 Number of monic irreducible polynomials of degree n in GF(5)[x,y].

Original entry on oeis.org

1, 30, 3410, 2330240, 7549603600, 118965950703744, 9309505329218297280, 3637689729211851543816960, 7105314552536912564123328420000, 69388718760088702173445263653542192000
Offset: 0

Views

Author

Max Alekseyev, Jan 16 2006

Keywords

Crossrefs

Showing 1-10 of 50 results. Next