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 1-6 of 6 results.

A006388 Number of sensed planar maps with n edges and without faces of degree 1.

Original entry on oeis.org

1, 1, 2, 6, 18, 74, 393, 2282, 14700, 99614, 703519, 5123598, 38279496
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A006384, A006389 (unsensed), A379433 (rooted).

Extensions

a(8)-a(12) from Sean A. Irvine, Mar 28 2017
a(0)=1 prepended by Andrew Howroyd, Jan 16 2025

A379433 Number of rooted planar maps with n edges and without faces of degree 1.

Original entry on oeis.org

1, 1, 3, 16, 96, 624, 4304, 31056, 232128, 1784752, 14043312, 112648848, 918456608, 7593649392, 63546379152, 537427956688, 4587713701248, 39488179213872, 342414691125104, 2989022121125136, 26249475365186016, 231786459869636464, 2056950693208881744
Offset: 0

Views

Author

Andrew Howroyd, Jan 14 2025

Keywords

Crossrefs

Cf. A000168, A006388 (sensed), A006389 (unsensed), A379434, A379435.

Programs

  • PARI
    seq(n)={my(z=x/(1 + x)^2, g=(-1 + 18*z + sqrt(1-12*z + O(x^(n+3)))^3) / (54*z^2)); Vec(x + g*(1-x)/(1+x))}

Formula

G.f.: x + G(x/(1 + x)^2)*(1 - x)/(1 + x) where G(x) is the g.f. of A000168.

A006393 Number of unsensed planar maps with n edges and without faces of degree 1 or 2.

Original entry on oeis.org

1, 0, 1, 4, 9, 32, 132, 597, 3064, 17114, 102274, 643907, 4219540
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A006385, A006389, A006392 (sensed), A379434 (rooted).

Extensions

a(8)-a(12) from Sean A. Irvine, Mar 29 2017
a(0)-a(1) prepended by Andrew Howroyd, Jan 16 2025

A006397 Number of unsensed planar maps with n edges and without faces or vertices of degree 1.

Original entry on oeis.org

1, 0, 1, 2, 4, 10, 34, 114, 475, 2104, 10177, 52012, 279874
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A006385, A006389, A006396 (sensed), A379435 (rooted).

Extensions

a(9)-a(12) from Sean A. Irvine, Mar 28 2017
a(0)-a(2) prepended by Andrew Howroyd, Jan 16 2025

A006401 Number of unsensed simple planar maps with n edges and without vertices of degree 1.

Original entry on oeis.org

1, 0, 0, 1, 1, 2, 5, 10, 28, 86, 285, 1055, 4211
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

A simple planar map is a planar map without loops or parallel edges. - Andrew Howroyd, Jan 16 2025

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A006385, A006389, A006395, A006400 (sensed), A379436 (rooted).

Extensions

a(11)-a(12) from Sean A. Irvine, Mar 31 2017
a(0)-a(2) prepended by Andrew Howroyd, Jan 16 2025

A380366 Number of unsensed combinatorial maps with n edges and without faces of degree 1.

Original entry on oeis.org

1, 1, 3, 11, 48, 291, 2464, 27146, 377966, 6239425
Offset: 0

Views

Author

Andrew Howroyd, Jan 28 2025

Keywords

Crossrefs

Cf. A006389 (planar), A214816, A380364 (rooted), A380365 (sensed).
Showing 1-6 of 6 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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