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 1-2 of 2 results.

A267180 Triangle read by rows: T(n,k) = number of rooted maps with n edges on a nonorientable surface of genus k (1 <= k <= n).

Original entry on oeis.org

1, 10, 4, 98, 84, 41, 982, 1340, 1380, 488, 10062, 19280, 31225, 23320, 8229, 105024, 263284, 592824, 696912, 516958, 164892, 1112757, 3486224, 10185056, 16662492, 19381145, 12980716, 4016613, 11934910, 45247084, 164037704, 348539072, 562395292, 590136856, 382630152, 112818960
Offset: 1

Views

Author

N. J. A. Sloane, Jan 16 2016

Keywords

Examples

			Triangle begins:
1,
10,4,
98,84,41,
982,1340,1380,488,
10062,19280,31225,23320,8229,
105024,263284,592824,696912,516958,164892,
1112757,3486224,10185056,16662492,19381145,12980716,4016613,
11934910,45247084,164037704,348539072,562395292,590136856,382630152,112818960
...
		

References

  • David M. Jackson and Terry I. Visentin, An Atlas of the Smaller Maps in Orientable and Nonorientable Surfaces, Chapman & Hall/CRC, circa 2000. See page 227.

Crossrefs

See A238396 for analog for orientable surfaces.
Columns give A007137, A006344.
Cf. A380235 (unrooted).

A118451 Number of rooted n-edge maps on a non-orientable genus-3 surface.

Original entry on oeis.org

41, 1380, 31225, 592824, 10185056, 164037704, 2525186319, 37596421940, 545585129474, 7758174844664, 108518545261360, 1497384373878512, 20426386710028260, 275940187259609296, 3696482210884173349
Offset: 3

Views

Author

Valery A. Liskovets, May 04 2006

Keywords

References

  • E. R. Canfield, Calculating the number of rooted maps on a surface, Congr. Numerantium, 76 (1990), 21-34.
  • D. M. Jackson and T. I. Visentin, An atlas of the smaller maps in orientable and nonorientable surfaces. CRC Press, Boca Raton, 2001.

Crossrefs

Programs

  • Maple
    R := sqrt(1-12*x) ;
    (R-1)*(R+1)*(68*R^5+280*R^4+588*R^3+808*R^2+416*R -(28*R^4+59*R^3+114*R^2+119*R+40)*sqrt(12*R*(R+2)))/96/R^5/(R+2)^3 ;
    g := series(%,x=0,101) ;
    for n from 3 to 100 do
        printf("%d %d\n",n,coeftayl(g,x=0,n)) ;
    end do: # R. J. Mathar, Oct 17 2012
  • Mathematica
    R = Sqrt[1-12x];
    (R-1)(R+1)(68R^5 + 280R^4 + 588R^3 + 808R^2 + 416R - (28R^4 + 59R^3 + 114R^2 + 119R + 40) Sqrt[12R(R+2)])/96/R^5/(R+2)^3 + O[x]^18 // CoefficientList[#, x]& // Drop[#, 3]& (* Jean-François Alcover, Aug 28 2019 *)

Formula

O.g.f.: (R-1) *(R+1) *(68*R^5 +280*R^4 +588*R^3 +808*R^2 +416*R -(28*R^4+59*R^3+114*R^2+119*R+40)*sqrt(12*R*(R+2)))/ (96*R^5*(R+2)^3), where R=sqrt(1-12*x).
a(n) ~ 2^(2*n + 1/2) * 3^(n - 1/2) * n^(5/4) / Gamma(1/4) * (1 - 13*Gamma(1/4) / (8*sqrt(6)*n^(1/4)) + 23*Gamma(1/4)^2 / (32*Pi*sqrt(2*n)) - 23*Gamma(1/4) / (16*sqrt(6*Pi)*n^(3/4))). - Vaclav Kotesovec, Oct 27 2024
Showing 1-2 of 2 results.