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 1-5 of 5 results.

A350794 Number of digraphs on n unlabeled nodes with a global source and sink.

Original entry on oeis.org

1, 1, 2, 20, 574, 48854, 12444800, 9849180230, 25265372689314, 218451490123178684, 6562780921564838071734, 700270642102506752862044142, 269621199012416753533007480951824, 378982029174285293421133982496722212766, 1962119228020498122395242424575089505014761082
Offset: 1

Views

Author

Andrew Howroyd, Jan 19 2022

Keywords

Links

Crossrefs

The labeled version is A350790.
Row sums of A350795.
Cf. A049531, A051421, A345258, A350360, A350796.

Programs

  • PARI
    A350794seq(15) \\ See link for program code.

A350795 Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled nodes with k arcs and a global source and sink, n >= 1, k = 0..max(1,n-1)*(n-2)+1.

Original entry on oeis.org

1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 6, 8, 4, 1, 0, 0, 0, 0, 1, 16, 70, 140, 159, 113, 53, 17, 4, 1, 0, 0, 0, 0, 0, 1, 33, 313, 1439, 3941, 7297, 9750, 9840, 7717, 4788, 2377, 946, 309, 80, 18, 4, 1, 0, 0, 0, 0, 0, 0, 1, 58, 998, 8447, 43269, 152135, 396011
Offset: 1

Views

Author

Andrew Howroyd, Jan 21 2022

Keywords

Examples

			Triangle begins:
  [1] 1;
  [2] 0, 1;
  [3] 0, 0, 1, 1;
  [4] 0, 0, 0, 1, 6,  8,  4,   1;
  [5] 0, 0, 0, 0, 1, 16, 70, 140, 159, 113, 53, 17, 4, 1;
  ...

Links

Crossrefs

Row sums are A350794.
Column sums are A350796.
The labeled version is A350791.
Cf. A057277, A057278, A350797.

Programs

  • PARI
    \\ See PARI link in A350794 for program code.
{ my(A=A350795triang(5)); for(n=1, #A, print(A[n])) }

A350798 Number of unlabeled digraphs with n arcs and a global source (or sink).

Original entry on oeis.org

1, 1, 2, 6, 21, 84, 387, 1953, 10802, 64267, 408489, 2750686, 19518841, 145236878, 1128884559, 9135566309, 76758391212, 667993213393, 6008434514996, 55755719348210, 532896254763646, 5238211003916685, 52885470406233727, 547751388283907208, 5813693205313803535, 63170000832869927871
Offset: 0

Views

Author

Andrew Howroyd, Jan 21 2022

Keywords

Crossrefs

Column sums of A350797.
Cf. A350360, A350752, A350796, A350906, A350907.

Programs

A350906 Number of unlabeled initially-finally connected digraphs with n arcs.

Original entry on oeis.org

1, 1, 2, 5, 16, 56, 241, 1111, 5748, 31912, 190328, 1204317, 8050341, 56516303, 415128256, 3179020729, 25308005049, 208918893640, 1784451646305, 15739926014382, 143130061546156, 1339761466105929, 12891329514544223, 127351374611721837, 1290198076415425548, 13390893744153374776
Offset: 0

Views

Author

Andrew Howroyd, Jan 21 2022

Keywords

Crossrefs

Column sums of A057278.
Cf. A049531 (by vertices), A350752, A350796, A350798, A350907.

Programs

A350907 Number of unlabeled initially connected digraphs with n arcs.

Original entry on oeis.org

1, 1, 3, 8, 29, 111, 522, 2604, 14459, 85796, 544753, 3659313, 25902251, 192171887, 1489090036, 12011329453, 100583184087, 872346402439, 7819597099285, 72313198682817, 688784601395670, 6747614973580663, 67896777481378196, 700913648767703716, 7415270780191604414, 80316990564932960558
Offset: 0

Views

Author

Andrew Howroyd, Jan 21 2022

Keywords

Crossrefs

Column sums of A057277.
Cf. A051421 (by vertices), A350752, A350796, A350798, A350906.

Programs

Showing 1-5 of 5 results.

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

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