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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A094037 Number of connected 6-element antichains on a labeled n-set.

Original entry on oeis.org

0, 0, 0, 0, 1, 1345, 738741, 185165477, 29458046177, 3541242666045, 354515664467077, 31326419674855789, 2535191648955942273, 192567615994193565125, 13962461827318220986133, 978010022290154153870661
Offset: 0

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Author

Goran Kilibarda, Vladeta Jovovic, Apr 22 2004

Keywords

Crossrefs

Formula

E.g.f.: (exp(63*x) - 30*exp(47*x) + 120*exp(39*x) + 60*exp(35*x) + 60*exp(33*x) - 18*exp(32*x) - 339*exp(31*x) - 720*exp(29*x) + 810*exp(27*x) + 120*exp(26*x) + 480*exp(25*x) + 480*exp(24*x) - 600*exp(23*x) - 720*exp(22*x) - 240*exp(21*x) - 900*exp(20*x) + 1740*exp(19*x) + 615*exp(18*x) + 180*exp(17*x) + 435*exp(16*x) - 1445*exp(15*x) - 3270*exp(14*x) + 1710*exp(13*x) + 4620*exp(12*x) - 3360*exp(11*x) - 3210*exp(10*x) + 3360*exp(9*x) + 6810*exp(8*x) - 12465*exp(7*x) + 5985*exp(6*x) + 7110*exp(5*x) - 18555*exp(4*x) + 17884*exp(3*x) - 8352*exp(2*x) + 1764*exp(x) - 120)/6!.

A084883 Number of (k,m,n)-multiantichains of multisets with k=3 and m=6.

Original entry on oeis.org

1, 3, 64, 8022, 6822072, 14068794534, 26314469636622, 37310026340520678, 42667193588371160460, 42169580808988409450310, 37803058273249518925923210, 31733179110752959606870643334
Offset: 0

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Author

Goran Kilibarda, Vladeta Jovovic, Jun 10 2003

Keywords

Comments

By a (k,m,n)-multiantichain of multisets we mean an m-multiantichain of k-bounded multisets on an n-set. The elements of a multiantichain could have the multiplicities greater than 1. A multiset is called k-bounded if every its element has the multiplicity not greater than k-1.

Crossrefs

Formula

a(n) = (1/6!)*(729^n - 30*486^n + 120*378^n + 60*324^n + 60*294^n - 360*279^n - 12*276^n - 720*252^n + 45*243^n + 90*234^n + 720*231^n + 120*216^n + 720*210^n - 240*205^n + 360*196^n - 720*189^n - 180*187^n + 720*186^n - 720*176^n + 120*168^n - 720*167^n + 360*165^n - 900*162^n - 720*157^n + 180*156^n + 720*148^n - 240*145^n + 720*138^n + 30*134^n - 240*129^n + 2700*126^n - 360*120^n + 180*111^n + 900*108^n - 20*102^n + 450*98^n - 5400*93^n - 5400*84^n + 685*81^n + 1350*78^n + 5400*77^n + 5400*70^n - 5400*63^n + 900*56^n - 8220*54^n + 16440*42^n + 2740*36^n - 16440*31^n + 4275*27^n + 4110*26^n - 25650*18^n + 25650*14^n + 10474*9^n - 20948*6^n + 7560*3^n).

A069403 a(n) = 2*Fibonacci(2*n+1) - 1.

Original entry on oeis.org

1, 3, 9, 25, 67, 177, 465, 1219, 3193, 8361, 21891, 57313, 150049, 392835, 1028457, 2692537, 7049155, 18454929, 48315633, 126491971, 331160281, 866988873, 2269806339, 5942430145, 15557484097, 40730022147, 106632582345, 279167724889, 730870592323, 1913444052081
Offset: 0

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Author

R. H. Hardin, Mar 22 2002

Keywords

Comments

Half the number of n X 3 binary arrays with a path of adjacent 1's and a path of adjacent 0's from top row to bottom row.
Indices of A017245 = 9*n + 7 = 7, 16, 25, 34, for submitted A153819 = 16, 34, 88,. A153819(n) = 9*a(n) + 7 = 18*F(2*n+1) -2; F(n) = Fibonacci = A000045, 2's = A007395. Other recurrence: a(n) = 4*a(n-1) - 4*a(n-2) + a(n-3). - Paul Curtz, Jan 02 2009

Crossrefs

Cf. 1 X n A000225, 2 X n A016269, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.
Equals A052995 - 1.
Bisection of A001595, A062114, A066983.

Programs

  • GAP
    List([0..30], n-> 2*Fibonacci(2*n+1)-1); # G. C. Greubel, Jul 11 2019
  • Magma
    [2*Fibonacci(2*n+1)-1: n in [0..30]]; // Vincenzo Librandi, Apr 18 2011
    
  • Mathematica
    a[n_]:= a[n] = 3a[n-1] - 3a[n-3] + a[n-4]; a[0] = 1; a[1] = 3; a[2] = 9; a[3] = 25; Table[ a[n], {n, 0, 30}]
    Table[2*Fibonacci[2*n+1]-1, {n,0,30}] (* G. C. Greubel, Apr 22 2018 *)
    LinearRecurrence[{4,-4,1},{1,3,9},30] (* Harvey P. Dale, Sep 22 2020 *)
  • PARI
    a(n) = 2*fibonacci(2*n+1)-1 \\ Charles R Greathouse IV, Jun 11 2015
    
  • PARI
    Vec((1-x+x^2)/((1-x)*(1-3*x+x^2)) + O(x^30)) \\ Colin Barker, Nov 02 2016
    
  • Sage
    [2*fibonacci(2*n+1)-1 for n in (0..30)] # G. C. Greubel, Jul 11 2019
    

Formula

a(0) = 1, a(1) = 3, a(2) = 9, a(3) = 25; a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4).
a(n) = 3*a(n-1) - a(n-2) + 1 for n>1, a(1) = 3, a(0) = 0. - Reinhard Zumkeller, May 02 2006
From R. J. Mathar, Feb 23 2009: (Start)
a(n) = 4*a(n-1) - 4*a(n-2) + a(n-3).
G.f.: (1-x+x^2)/((1-x)*(1-3*x+x^2)). (End)
a(n) = 1 + 2*Sum_{k=0..n} Fibonacci(2*k) = 1+2*A027941(n). - Gary Detlefs, Dec 07 2010
a(n) = (2^(-n)*(-5*2^n -(3-sqrt(5))^n*(-5+sqrt(5)) +(3+sqrt(5))^n*(5+sqrt(5))))/5. - Colin Barker, Nov 02 2016

Extensions

Simpler definition from Vladeta Jovovic, Mar 19 2003

A025211 Expansion of 1/((1-2x)(1-3x)(1-4x)(1-5x)).

Original entry on oeis.org

1, 14, 125, 910, 5901, 35574, 204205, 1132670, 6129101, 32566534, 170691885, 885423630, 4556561101, 23305343894, 118631189165, 601616805790, 3042056477901, 15346559343654, 77279066272045, 388583895311150, 1951684190615501, 9793511186181814, 49108010998116525
Offset: 0

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Author

Keywords

Comments

This gives the fourth column of the Sheffer triangle A143494 (2-restricted Stirling2 numbers). See the e.g.f. given below, and comments on the general case under A193685. - Wolfdieter Lang, Oct 08 2011

Crossrefs

Programs

Formula

If we define f(m,j,x) = Sum_{k=j..m} binomial(m,k)*stirling2(k,j)*x^(m-k) then a(n-3) = (-1)^(n-1)*f(n,3,-5), (n >= 3). - Milan Janjic, Apr 26 2009
If we define f(m,j,x) = Sum_{k=j..m} binomial(m,k)*stirling2(k,j)*x^(m-k) then a(n-3) = f(n,3,2), (n >= 3). - Milan Janjic, Apr 26 2009
a(n) = 3^(n+3)/2 - 2*4^(n+2) - 2^(n+2)/3 + 5^(n+3)/6. - R. J. Mathar, Mar 22 2011
O.g.f.: 1/((1-2*x)*(1-3*x)*(1-4*x)*(1-5*x)).
E.g.f.: (d^3/dx^3) (exp(2*x)*((exp(x)-1)^3)/3!). See the Sheffer comment given above. - Wolfdieter Lang, Oct 08 2011

A051113 Number of monotone Boolean functions of n variables with 5 mincuts.

Original entry on oeis.org

0, 0, 0, 0, 6, 2146, 304752, 25400564, 1557306954, 78817977462, 3513106214484, 143429796694888, 5501383287745422, 201652447559180618, 7148287976359243896, 247151326758617289372, 8386495692534098616210, 280574309728711561269214, 9286566498536162168164188
Offset: 0

Views

Author

Vladeta Jovovic, Goran Kilibarda, and Zoran Maksimovic

Keywords

References

  • J. L. Arocha, Antichains in ordered sets, (in Spanish) An. Inst. Mat. UNAM, vol. 27, 1987, 1-21.
  • V. Jovovic, G. Kilibarda, On enumeration of the class of all monotone Boolean function, Belgrade, 1999, in preparation.

Crossrefs

Formula

a(n) = 1/5! * (32^n-20 * 24^n+ 60 * 20^n+ 20 * 18^n+ 10 * 17^n-110 * 16^n-120 * 15^n+ 150 * 14^n+ 120 * 13^n-240 * 12^n+ 20 * 11^n+ 240 * 10^n+ 40 * 9^n-205 * 8^n+ 60 * 7^n-210 * 6^n+ 210 * 5^n+ 50 * 4^n-100 * 3^n+ 24 * 2^n).
G.f.: -2*x^4*(140561100029952000*x^15 -73258140662784000*x^14 -8396658614522880*x^13 +15284070825850368*x^12 -4918391338514880*x^11 +748203166795520*x^10 -45197506544400*x^9 -3280961201664*x^8 +887950976060*x^7 -80597007540*x^6 +3942400065*x^5 -98697251*x^4 +532770*x^3 +26970*x^2 -335*x -3) / ((2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)*(8*x -1)*(9*x -1)*(10*x -1)*(11*x -1)*(12*x -1)*(13*x -1)*(14*x -1)*(15*x -1)*(16*x -1)*(17*x -1)*(18*x -1)*(20*x -1)*(24*x -1)*(32*x -1)). - Colin Barker, Jul 14 2013

Extensions

More terms from Colin Barker, Jul 14 2013

A051114 Number of monotone Boolean functions of n variables with 6 mincuts.

Original entry on oeis.org

0, 0, 0, 0, 1, 1380, 759457, 192504214, 31169837405, 3827970163920, 392135190780649, 35468973527445018, 2937270598777421269, 228156280366446932500, 16904255174464832812001, 1208995011493806361868862, 84197134590686932418878093, 5746616155270206518199693720
Offset: 0

Views

Author

Vladeta Jovovic, Goran Kilibarda, and Zoran Maksimovic

Keywords

References

  • J. L. Arocha, Antichains in ordered sets, (in Spanish) An. Inst. Mat. UNAM, vol. 27, 1987, 1-21.
  • V. Jovovic and G. Kilibarda, On enumeration of the class of all monotone Boolean functions, Belgrade, 1999, in preparation.

Crossrefs

Formula

a(n) = (1/6!)*(64^n-30 * 48^n+ 120 * 40^n+ 60 * 36^n+ 60 * 34^n-12 * 33^n-345 * 32^n-720 * 30^n+ 810 * 28^n+ 120 * 27^n+ 480 * 26^n+ 360 * 25^n-480 * 24^n-720 * 23^n-240 * 22^n-540 * 21^n+ 1380 * 20^n+ 750 * 19^n+ 60 * 18^n-210 * 17^n-1535 * 16^n-1820 * 15^n+ 2250 * 14^n+ 1800 * 13^n-2820 * 12^n+ 300 * 11^n+ 2040 * 10^n+ 340 * 9^n-1815 * 8^n+ 510 * 7^n-1350 * 6^n+ 1350 * 5^n+ 274 * 4^n-548 * 3^n+ 120 * 2^n).

Extensions

More terms from Colin Barker, Nov 26 2014

A027650 Poly-Bernoulli numbers B_n^(k) with k=-3.

Original entry on oeis.org

1, 8, 46, 230, 1066, 4718, 20266, 85310, 354106, 1455278, 5938186, 24104990, 97478746, 393095438, 1581931306, 6356390270, 25511588986, 102304505198, 409992599626, 1642294397150, 6576150108826, 26325519044558, 105364834103146, 421647614381630, 1687155299822266
Offset: 0

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Keywords

Comments

a(n) is also the number of acyclic orientations of the complete bipartite graph K_{3,n}. - Vincent Pilaud, Sep 15 2020

Crossrefs

First differences of A016269.
Row 3 of array A099594.

Programs

  • Magma
    [6*4^n-6*3^n+2^n: n in [0..30]]; // Vincenzo Librandi, Jul 17 2011
    
  • Maple
    a:= (n, k) -> (-1)^n*sum((-1)^j*j!*Stirling2(n, j)/(j+1)^k, j=0..n);
    seq(a(n, -3), n = 0..30);
  • Mathematica
    Table[6*4^n-6*3^n+2^n, {n,0,30}] (* G. C. Greubel, Feb 07 2018 *)
  • PARI
    Vec((1-x)/((1-2*x)*(1-3*x)*(1-4*x)) + O(x^30)) \\ Michel Marcus, Feb 13 2015
    
  • SageMath
    [2^n -6*3^n +6*4^n for n in (0..30)] # G. C. Greubel, Aug 02 2022

Formula

a(n) = 6*4^n - 6*3^n + 2^n. - Vladeta Jovovic, Nov 14 2003
G.f.: (1-x)/((1-2*x)*(1-3*x)*(1-4*x)).
E.g.f.: exp(2*x) - 6*exp(3*x) + 6*exp(4*x). - G. C. Greubel, Aug 02 2022

A051115 Number of monotone Boolean functions of n variables with 7 mincuts.

Original entry on oeis.org

0, 0, 0, 0, 0, 490, 1308270, 1085660748, 483349680164, 147791677696350, 35419166732721930, 7189973830216081696, 1298090729995668204288, 215276329320562758744210, 33531967207612008887673350
Offset: 0

Views

Author

Vladeta Jovovic, Goran Kilibarda, Zoran Maksimovic

Keywords

References

  • J. L. Arocha, Antichains in ordered sets, (in Spanish) An. Inst. Mat. UNAM, vol. 27, 1987, 1-21.
  • V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6)
  • V. Jovovic, G. Kilibarda, On enumeration of the class of all monotone Boolean functions, Belgrade, 1999, in preparation.

Crossrefs

A051116 Number of monotone Boolean functions of n variables with 8 mincuts.

Original entry on oeis.org

0, 0, 0, 0, 0, 115, 1613250, 4693213105, 5971431466764, 4657267944250425, 2654563364004395160, 1223795727111874798255, 485987045749653063943998, 173253367143529540187635315, 57037488183550191520963561230
Offset: 0

Views

Author

Vladeta Jovovic, Goran Kilibarda, and Zoran Maksimovic

Keywords

References

  • J. L. Arocha, Antichains in ordered sets, (in Spanish) An. Inst. Mat. UNAM, vol. 27, 1987, 1-21.
  • V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6)
  • V. Jovovic, G. Kilibarda, On enumeration of the class of all monotone Boolean functions, Belgrade, 1999, in preparation.

Crossrefs

A051117 Number of monotone Boolean functions of n variables with 9 mincuts.

Original entry on oeis.org

0, 0, 0, 0, 0, 20, 1484230, 15946757960, 60089234465176, 122281201867047920, 168329227672583040430, 178185327268349957044060, 156921594738520322214197672, 121014019160263331691800711500
Offset: 0

Views

Author

Vladeta Jovovic, Goran Kilibarda, and Zoran Maksimovic

Keywords

References

  • J. L. Arocha, Antichains in ordered sets, (in Spanish) An. Inst. Mat. UNAM, vol. 27, 1987, 1-21.
  • V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6)
  • V. Jovovic, G. Kilibarda, On enumeration of the class of all monotone Boolean functions, Belgrade, 1999, in preparation.

Crossrefs

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