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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A000502 Number of genus 0 rooted maps with 6 faces and n vertices.

Original entry on oeis.org

42, 1586, 31388, 442610, 5030004, 49145460, 429166584, 3435601554, 25658464260, 181055975100, 1218601601672, 7880146275092, 49238911113224, 298652277299880, 1764885293279472, 10192638073849554, 57674223198273444, 320430129184331628, 1751190732477786600, 9428906326013866076
Offset: 5

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Author

Keywords

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • 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 6 of A269920.
Column 0 of A270410.

Programs

  • Mathematica
    CoefficientList[ x(1-Sqrt[1-4x])(105+92x-(84+76x)Sqrt[1-4x])/(1-4x)^7/x^2 + O[x]^30, x] (* Jean-François Alcover, Feb 09 2016 *)
  • PARI
    seq(n)={my(g=sqrt(1-4*x + O(x*x^n))); Vec((1-g)*(105+92*x - (84+76*x)*g)/((1-4*x)^7))} \\ Andrew Howroyd, Mar 28 2021

Formula

G.f.: x^4*(1-sqrt(1-4*x))*(105+92*x-(84+76*x)*sqrt(1-4*x))/(1-4*x)^7. - Sean A. Irvine, Nov 14 2010

Extensions

More terms from Sean A. Irvine, Nov 14 2010

A006294 Number of rooted planar maps with n edges.

Original entry on oeis.org

1, 1, 5, 22, 164, 1030, 8885, 65954, 614404, 5030004, 49145460, 429166584, 4331674512, 39599553708, 409230997461, 3871362876810, 40730958917220, 395684757649324, 4222043580320852, 41894315105061848, 452123832420881296
Offset: 0

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Author

Keywords

References

  • 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.
  • T. R. S. Walsh and A. B. Lehman, Counting rooted maps by genus, J. Comb. Thy B13 (1972), 122-141 and 192-218.

Crossrefs

Row maxima of A269920.

Extensions

More terms from Sean A. Irvine, Feb 24 2017

A380240 Array read by antidiagonals: A(n,k) is the number of sensed planar maps with n vertices and k faces including one distinguished outside face, n >= 1, k >= 1.

Original entry on oeis.org

1, 1, 2, 3, 1, 4, 12, 8, 2, 10, 48, 64, 25, 3, 26, 196, 412, 314, 78, 6, 80, 798, 2458, 2976, 1478, 270, 14, 246, 3248, 13452, 23588, 18844, 6748, 926, 34, 810, 13184, 70330, 166050, 192096, 110714, 30168, 3305, 95, 2704, 53416, 353716, 1074472, 1676668, 1397484, 613884, 132734, 11868, 280, 9252
Offset: 1

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Author

Andrew Howroyd, Jan 21 2025

Keywords

Comments

The number of edges is n + k - 2.

Examples

			Array begins:
==============================================================
n\k |  1    2      3      4       5       6       7      8 ...
----+---------------------------------------------------------
  1 |  1    1      2      4      10      26      80    246 ...
  2 |  1    3     12     48     196     798    3248  13184 ...
  3 |  1    8     64    412    2458   13452   70330 353716 ...
  4 |  2   25    314   2976   23588  166050 1074472 ...
  5 |  3   78   1478  18844  192096 1676668 ...
  6 |  6  270   6748 110714 1397484 ...
  7 | 14  926  30168 613884 ...
  8 | 34 3305 132734 ...
   ...
		

Crossrefs

Columns 1..2 are A002995, A060404.
Rows 1..2 are A003239(n-1), A103943.
Antidiagonal sums are A103937.
Cf. A269920 (rooted), A379430 (sensed with no root).
Previous Showing 11-13 of 13 results.