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 11 results. Next

A006300 Number of rooted maps with n edges on torus.

Original entry on oeis.org

1, 20, 307, 4280, 56914, 736568, 9370183, 117822512, 1469283166, 18210135416, 224636864830, 2760899996816, 33833099832484, 413610917006000, 5046403030066927, 61468359153954656, 747672504476150374, 9083423595292949240, 110239596847544663002, 1336700736225591436496, 16195256987701502444284
Offset: 2

Views

Author

Keywords

References

  • E. R. Canfield, Calculating the number of rooted maps on a surface, Congr. Numerantium, 76 (1990), 21-34.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • T. R. S. Walsh, Combinatorial Enumeration of Non-Planar Maps. Ph.D. Dissertation, Univ. of Toronto, 1971.

Crossrefs

Column k=1 of A238396.
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, this sequence, A006301, A104742, A215402, A238355, A238356, A238357, A238358, A238359, A238360.

Programs

  • Maple
    R:=sqrt(1-12*x): seq(coeff(convert(series((R-1)^2/(12*R^2*(R+2)),x,50),polynom),x,n),n=2..25); (Pab Ter)
  • Mathematica
    Drop[With[{c=Sqrt[1-12x]},CoefficientList[Series[(c-1)^2/(12c^2 (c+2)), {x,0,30}],x]],2] (* Harvey P. Dale, Jun 14 2011 *)
  • PARI
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A006300_ser(N) = my(y = A005159_ser(N+1)); y*(y-1)^2/(3*(y-2)^2*(y+2));
    Vec(A006300_ser(21)) \\ Gheorghe Coserea, Jun 02 2017

Formula

G.f.: (R-1)^2/(12*R^2*(R+2)) where R=sqrt(1-12*x); a(n) is asymptotic to 12^n/24. - Pab Ter (pabrlos2(AT)yahoo.com), Nov 07 2005
a(n) = Sum_{k=0..n-2} 2^(n-3-k)*(3^(n-1)-3^k)*binomial(n+k,k). - Ruperto Corso, Dec 18 2011
D-finite with recurrence: n*a(n) +22*(-n+1)*a(n-1) +4*(22*n-65)*a(n-2) +96*(5*n-4)*a(n-3) +576*(-2*n+7)*a(n-4)=0. - R. J. Mathar, Feb 20 2020

Extensions

Bender et al. give 20 terms.
More terms from Pab Ter (pabrlos2(AT)yahoo.com), Nov 07 2005
More terms from Joerg Arndt, Feb 26 2014

A269919 Triangle read by rows: T(n,g) is the number of rooted maps with n edges on an orientable surface of genus g.

Original entry on oeis.org

1, 2, 9, 1, 54, 20, 378, 307, 21, 2916, 4280, 966, 24057, 56914, 27954, 1485, 208494, 736568, 650076, 113256, 1876446, 9370183, 13271982, 5008230, 225225, 17399772, 117822512, 248371380, 167808024, 24635754, 165297834, 1469283166, 4366441128
Offset: 0

Views

Author

Gheorghe Coserea, Mar 07 2016

Keywords

Comments

Row n contains floor((n+2)/2) terms.
Equivalently, T(n,g) is the number of rooted bipartite quadrangulations with n faces of an orientable surface of genus g.

Examples

			Triangle starts:
n\g    [0]          [1]          [2]          [3]          [4]
[0]    1;
[1]    2;
[2]    9,           1;
[3]    54,          20;
[4]    378,         307,         21;
[5]    2916,        4280,        966;
[6]    24057,       56914,       27954,       1485;
[7]    208494,      736568,      650076,      113256;
[8]    1876446,     9370183,     13271982,    5008230,     225225;
[9]    17399772,    117822512,   248371380,   167808024,   24635754;
[10]   ...
		

Crossrefs

Same as A238396 except for the zeros.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g<0 || g>n/2 = 0; T[n_, g_] := T[n, g] = ((4n-2)/ 3 T[n-1, g] + (2n-3)(2n-2)(2n-1)/12 T[n-2, g-1] + 1/2 Sum[(2k-1)(2(n-k)- 1) T[k-1, i] T[n-k-1, g-i], {k, 1, n-1}, {i, 0, g}])/((n+1)/6);
    Table[T[n, g], {n, 0, 10}, {g, 0, n/2}] // Flatten (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    N = 9; gmax(n) = n\2;
    Q = matrix(N+1, N+1);
    Qget(n, g) = { if (g < 0 || g > n/2, 0, Q[n+1, g+1]) };
    Qset(n, g, v) = { Q[n+1, g+1] = v };
    Quadric({x=1}) = {
      Qset(0, 0, x);
      for (n = 1, N, for (g = 0, gmax(n),
        my(t1 = (1+x)*(2*n-1)/3 * Qget(n-1, g),
           t2 = (2*n-3)*(2*n-2)*(2*n-1)/12 * Qget(n-2, g-1),
           t3 = 1/2 * sum(k = 1, n-1, sum(i = 0, g,
           (2*k-1) * (2*(n-k)-1) * Qget(k-1, i) * Qget(n-k-1, g-i))));
        Qset(n, g, (t1 + t2 + t3) * 6/(n+1))));
    };
    Quadric();
    concat(vector(N+1, n, vector(1 + gmax(n-1), g, Qget(n-1, g-1))))

Formula

(n+1)/6 * T(n, g) = (4*n-2)/3 * T(n-1, g) + (2*n-3)*(2*n-2)*(2*n-1)/12 * T(n-2, g-1) + 1/2 * Sum_{k=1..n-1} Sum_{i=0..g} (2*k-1) * (2*(n-k)-1) * T(k-1, i) * T(n-k-1, g-i) for all n >= 1 and 0 <= g <= n/2, with the initial conditions T(0,0) = 1 and T(n,g) = 0 for g < 0 or g > n/2.
For column g, as n goes to infinity we have T(n,g) ~ t(g) * n^(5*(g-1)/2) * 12^n, where t(g) = (A269418(g)/A269419(g)) / (2^(g-2) * gamma((5*g-1)/2)) and gamma is the Gamma function.

A006301 Number of rooted genus-2 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 21, 966, 27954, 650076, 13271982, 248371380, 4366441128, 73231116024, 1183803697278, 18579191525700, 284601154513452, 4272100949982600, 63034617139799916, 916440476048146056, 13154166812674577412, 186700695099591735024, 2623742783421329300190, 36548087103760045010148, 505099724454854883618924
Offset: 0

Views

Author

Keywords

References

  • E. R. Canfield, Calculating the number of rooted maps on a surface, Congr. Numerantium, 76 (1990), 21-34.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • T. R. S. Walsh, Combinatorial Enumeration of Non-Planar Maps. Ph.D. Dissertation, Univ. of Toronto, 1971.

Crossrefs

Column k=2 of A238396.
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, this sequence, A104742, A215402, A238355, A238356, A238357, A238358, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 2];
    Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A006301_ser(N) = {
      my(y=A005159_ser(N+1));
      -y*(y-1)^4*(4*y^4 - 16*y^3 + 153*y^2 - 148*y + 196)/(9*(y-2)^7*(y+2)^4);
    };
    concat([0,0,0,0], Vec(A006301_ser(19))) \\ Gheorghe Coserea, Jun 02 2017

Extensions

More terms from Joerg Arndt, Feb 26 2014

A104742 Number of rooted maps of (orientable) genus 3 containing n edges.

Original entry on oeis.org

1485, 113256, 5008230, 167808024, 4721384790, 117593590752, 2675326679856, 56740864304592, 1137757854901806, 21789659909226960, 401602392805341924, 7165100439281414160, 124314235272290304540, 2105172926498512761984, 34899691847703927826500, 567797719808735191344672, 9084445205688065541367710
Offset: 6

Views

Author

Valery A. Liskovets, Mar 22 2005

Keywords

Crossrefs

Column k=3 of A238396.
Cf. A104596 (unrooted maps).
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, this sequence, A215402, A238355, A238356, A238357, A238358, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 3];
    Table[a[n], {n, 6, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A104742_ser(N) = {
      my(y=A005159_ser(N+1));
      y*(y-1)^6*(460*y^8 - 3680*y^7 + 63055*y^6 - 198110*y^5 + 835954*y^4 - 1408808*y^3 + 1986832*y^2 - 1462400*y + 547552)/(81*(y-2)^12*(y+2)^7)
    };
    Vec(A104742_ser(17))  \\ Gheorghe Coserea, Jun 02 2017

A238355 Number of rooted maps of genus 5 containing n edges.

Original entry on oeis.org

59520825, 8608033980, 672868675017, 37680386599440, 1692352190653740, 64755027944420400, 2190839204960030106, 67194704604610557072, 1901727022434216910002, 50322107898515282999256, 1257582616997225194094310, 29916524874047762719113408, 681758763997451748190036272, 14960113428664295584816860864
Offset: 10

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Row sums of A269925.
Column g=5 of A269919.
Cf. A239918 (unrooted sensed), A348798 (unrooted unsensed)
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, this sequence, A238356, A238357, A238358, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 5];
    Table[a[n], {n, 10, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396
    
  • PARI
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A238355_ser(N) = {
      my(y=A005159_ser(N+1));
      y*(y-1)^10*(3149956*y^16 - 50399296*y^15 + 1641189689*y^14 - 12178227918*y^13 + 118643174857*y^12 - 572499071300*y^11 + 2690451915197*y^10 - 8657342508522*y^9 + 23652302179098*y^8 - 49891059998872*y^7 + 84432024838000*y^6 - 112355956173344*y^5 + 115338024848256*y^4 - 88846084908160*y^3 + 48488699816960*y^2 - 16837415717888*y + 2841312026112)/(243*(y-2)^22*(y+2)^13);
    };
    Vec(A238355_ser(14)) \\ Gheorghe Coserea, Jun 02 2017

A238356 Number of rooted maps of genus 6 containing n edges.

Original entry on oeis.org

24325703325, 4416286056750, 425671555397220, 28948474436455224, 1558252224413413380, 70639804918689629112, 2802850363447807024080, 99911395098598706576856, 3259947795252652107008514, 98729808377337068918681196, 2805432194025270702468165744
Offset: 12

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Column g=6 of A269919.
Cf. A239919 (unrooted sensed), A348798 (unrooted unsensed).
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, A238355, this sequence, A238357, A238358, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 6];
    Table[a[n], {n, 12, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396
    
  • PARI
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A238356_ser(N) = {
      my(y=A005159_ser(N+1));
      -y*(y-1)^12*(3091382412*y^20 - 61827648240*y^19 + 2494741456179*y^18 - 23821030780564*y^17 + 297709107215018*y^16 - 1898397937026724*y^15 + 11996625283021532*y^14 - 53079600835119544*y^13 + 206468965657569764*y^12 - 637634273350412392*y^11 + 1660605297373850222*y^10 - 3573247507645221112*y^9 + 6390852378647917144*y^8 - 9449999309170921856*y^7 + 11435897504002339264*y^6 - 11175919884930946304*y^5 + 8621441033651120896*y^4 - 5068129528843341824*y^3 + 2141653827725309440*y^2 - 581932716954417152*y + 76958488611567616)/(2187*(y-2)^27*(y+2)^16);
    };
    Vec(A238356_ser(11)) \\ Gheorghe Coserea, Jun 02 2017

A238357 Number of genus-7 rooted maps with n edges.

Original entry on oeis.org

14230536445125, 3128879373858000, 360626952084151500, 29001816720933903504, 1828003659229082834100, 96187365300257285300064, 4395215998078319892167640, 179153431308203084149883760, 6641365771586560905099092466, 227189907562197156785567456832, 7252879937219595844346639732688
Offset: 14

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Column g=7 of A269919.
Cf. A239921 (unrooted sensed), A348800 (unrooted unsensed).
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, A238355, A238356, this sequence, A238358, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 7];
    Table[a[n], {n, 14, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396
    
  • PARI
    system("wget http://oeis.org/A238357/a238357.txt");
    A005159_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-12*x))/(6*x);
    A238357_ser(N) = subst(read("a238357.txt"), 'y, A005159_ser(N+14));
    Vec(A238357_ser(11)) \\ Gheorghe Coserea, Jun 03 2017

A238358 Number of genus-8 rooted maps with n edges.

Original entry on oeis.org

11288163762500625, 2927974178219879250, 394372363395179602125, 36751560969705187643982, 2663973075006196131775590, 160098273686603663417293308, 8303278159618015743881266599, 381958851175370643701603049354, 15896435050196091382215375181044, 607566907750822335161584110201960
Offset: 16

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Column g=8 of A269919.
Cf. A239922 (unrooted sensed), A348801 (unrooted unsensed).
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, A238355, A238356, A238357, this sequence, A238359, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 8];
    Table[a[n], {n, 16, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396

A238359 Number of genus-9 rooted maps with n edges.

Original entry on oeis.org

11665426077721040625, 3498878057690404966500, 540996834819906946713375, 57494374008560749302297480, 4724172886681078698955547790, 320061005837218582787265273000, 18618409220753939214291224549409, 956146512935178711199035220384800, 44232688287025023758415781081779828, 1871678026675570344184400604255444240
Offset: 18

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Column g=9 of A269919.
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, A238355, A238356, A238357, A238358, this sequence, A238360.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 9];
    Table[a[n], {n, 18, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396

A238360 Number of genus-10 rooted maps with n edges.

Original entry on oeis.org

15230046989184655753125, 5199629454143883380553750, 909887917857275652461097750, 108861830345440643086946970900, 10021124647635764856828690342402, 757187906770815991999545249667404, 48918614114003431712044170834572688, 2779227352989564224315657269511192976, 141720718575991991799057452443438430580
Offset: 20

Views

Author

Joerg Arndt, Feb 26 2014

Keywords

Crossrefs

Column g=10 of A269919.
Rooted maps with n edges of genus g for 0 <= g <= 10: A000168, A006300, A006301, A104742, A215402, A238355, A238356, A238357, A238358, A238359, this sequence.

Programs

  • Mathematica
    T[0, 0] = 1; T[n_, g_] /; g < 0 || g > n/2 = 0; T[n_, g_] := T[n, g] = ((4 n - 2)/3 T[n - 1, g] + (2 n - 3) (2 n - 2) (2 n - 1)/12 T[n - 2, g - 1] + 1/2 Sum[(2 k - 1) (2 (n - k) - 1) T[k - 1, i] T[n - k - 1, g - i], {k, 1, n - 1}, {i, 0, g}])/((n + 1)/6);
    a[n_] := T[n, 10];
    Table[a[n], {n, 20, 30}] (* Jean-François Alcover, Jul 20 2018 *)
  • PARI
    \\ see A238396
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