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.

Previous Showing 11-20 of 30 results. Next

A078792 Number of unlabeled 3-trees on n vertices.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 5, 15, 58, 275, 1505, 9003, 56931, 372973, 2506312, 17165954, 119398333, 841244274, 5993093551, 43109340222, 312747109787, 2286190318744, 16826338257708, 124605344758149, 927910207739261, 6945172081954449, 52225283886702922
Offset: 1

Views

Author

Gordon F. Royle, Dec 05 2002

Keywords

Comments

A k-tree is recursively defined as follows: K_k is a k-tree and any k-tree on n+1 vertices is obtained by joining a new vertex to a k-clique in a k-tree on n vertices.

References

  • Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, page 328.

Crossrefs

Column k=3 of A370770.
Cf. A036362 (labeled 3-trees), A054581 (unlabeled 2-trees).

Extensions

More terms from Andrew R. Gainer, Dec 03 2011

A063687 Number of 2-trees rooted at any symmetric edge.

Original entry on oeis.org

1, 1, 1, 2, 3, 6, 10, 21, 38, 84, 156, 352, 677, 1562, 3054, 7148, 14196, 33603, 67474, 161121, 326519, 785305, 1603111, 3878194, 7965845, 19365811, 39983300, 97610247, 202424674, 495955345, 1032460679, 2537529717, 5300256499
Offset: 0

Views

Author

Vladeta Jovovic, Aug 22 2001

Keywords

References

  • F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 75, Eq. (3.5.9).

Crossrefs

A201702 Number of unlabeled 5-trees on n nodes.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 1, 2, 5, 15, 64, 342, 2321, 18578, 168287, 1656209, 17288336, 188006362, 2105867058, 24108331027, 280638347609, 3310098377912, 39462525169310, 474697793413215, 5754095507495584, 70216415130786725, 861924378411516159, 10636562125193377459
Offset: 1

Views

Author

Andrew R. Gainer, Dec 03 2011

Keywords

Comments

A k-tree is recursively defined as follows: K_k is a k-tree and any k-tree on n+1 vertices is obtained by joining a vertex to a k-clique in a k-tree on n vertices.

References

  • Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, page 328.

Crossrefs

Column k=5 of A370770.
Cf. A054581 (unlabeled 2-trees), A078792 (unlabeled 3-trees), A078793 (unlabeled 4-trees).

A202037 Number of unlabeled 6-trees on n nodes.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 1, 1, 2, 5, 15, 64, 342, 2344, 19090, 179562, 1878277, 21365403, 258965451, 3294561195, 43472906719, 589744428065, 8171396893523, 115094557122380, 1642269376265063, 23679803216530017, 344396036645439675, 5045351124912000756
Offset: 1

Views

Author

Andrew R. Gainer, Dec 09 2011

Keywords

Comments

A k-tree is recursively defined as follows: K_k is a k-tree and any k-tree on n+1 vertices is obtained by joining a vertex to a k-clique in a k-tree on n vertices.

References

  • Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, page 328.

Crossrefs

Column k=6 of A370770.
Cf. A054581 (unlabeled 2-trees), A078792 (unlabeled 3-trees), A078793 (unlabeled 4-trees), A201702 (unlabeled 5-trees)

A094610 Number of unlabeled 4-gonal 2-trees with n 4-gons.

Original entry on oeis.org

1, 1, 1, 3, 8, 32, 141, 749, 4304, 26492, 169263, 1115015, 7507211, 51466500, 358100288, 2523472751, 17978488711, 129325796854, 938234533024, 6858551493579, 50478955083341, 373815860588360, 2783730088637429, 20835514668765200, 156675846789962554, 1183195305751233833
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=4 of A340811.
Cf. A054581.

Extensions

Terms a(21) and beyond from Andrew Howroyd, May 09 2021

A094611 Number of unlabeled pentagonal 2-trees with n pentagons.

Original entry on oeis.org

1, 1, 1, 3, 11, 56, 359, 2597, 20386, 167819, 1429815, 12500748, 111595289, 1013544057, 9340950309, 87176935700, 822559721606, 7836316493485, 75293711520236, 728968295958626, 7105984356424859, 69697524828651997, 687448151462822966, 6815174949649428254
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=5 of A340811.
Cf. A054581.

Extensions

Terms a(21) and beyond from Andrew Howroyd, May 09 2021

A094637 Number of unlabeled hexagonal 2-trees with n hexagons.

Original entry on oeis.org

1, 1, 1, 4, 16, 103, 799, 7286, 71094, 729974, 7743818, 84307887, 937002302, 10595117272, 121568251909, 1412555701804, 16594126114458, 196829590326284, 2354703777373055, 28385225424840078, 344524656398655124, 4207569734885041198, 51674558137433627724
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=6 of A340811.
Cf. A054581.

Extensions

Terms a(21) and beyond from Andrew Howroyd, Feb 02 2021

A094651 Number of unlabeled heptagonal 2-trees with n heptagons.

Original entry on oeis.org

1, 1, 1, 4, 20, 158, 1539, 16970, 199879, 2460350, 31266165, 407461893, 5420228329, 73352481577, 1007312969202, 14008437540003, 196963172193733, 2796235114720116, 40038505601111596, 577693117173844307, 8392528734991449808, 122680472402091278920, 1803416089912665770579
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=7 of A340811.
Cf. A054581.

Extensions

Terms a(20) and beyond from Andrew Howroyd, Feb 02 2021

A094652 Number of unlabeled octagonal 2-trees with n octagons.

Original entry on oeis.org

1, 1, 1, 5, 26, 245, 2737, 35291, 483819, 6937913, 102666626, 1558022255, 24133790815, 380320794122, 6081804068869, 98490990290897, 1612634990857755, 26660840123167203, 444560998431678554, 7469779489114328514, 126375763235359105446, 2151342943131421629636
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=8 of A340811.
Cf. A054581.

Extensions

Terms a(20) and beyond from Andrew Howroyd, Feb 02 2021

A094653 Number of unlabeled 9-gonal 2-trees with n 9-gons.

Original entry on oeis.org

1, 1, 1, 5, 32, 343, 4505, 66603, 1045335, 17115162, 289107854, 5007144433, 88516438360, 1591949961503, 29053438148676, 536972307386326, 10034276171127780, 189331187319203010, 3603141751525175854, 69097496637591215442, 1334213677527481808220, 25922717218623692348237
Offset: 0

Views

Author

Vladeta Jovovic, Jun 06 2004

Keywords

Crossrefs

Column k=9 of A340811.
Cf. A054581.

Extensions

Terms a(19) and beyond from Andrew Howroyd, Feb 02 2021
Previous Showing 11-20 of 30 results. Next