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 1-10 of 14 results. Next

A241740 Number of partitions p of n such that (number of numbers in p of form 3k+2) < (number of numbers in p of form 3k).

Original entry on oeis.org

0, 0, 0, 1, 1, 1, 3, 4, 4, 7, 10, 12, 17, 24, 30, 40, 53, 70, 90, 118, 152, 194, 244, 316, 396, 497, 626, 784, 960, 1202, 1483, 1816, 2230, 2738, 3312, 4042, 4908, 5922, 7141, 8627, 10327, 12388, 14832, 17703, 21075, 25120, 29795, 35321, 41822, 49439, 58286
Offset: 0

Views

Author

Clark Kimberling, Apr 28 2014

Keywords

Comments

Each number in p is counted once, regardless of its multiplicity.

Examples

			a(8) counts these 4 partitions:  611, 431, 3311, 311111.
		

Crossrefs

Programs

  • Mathematica
    z = 40; f[n_] := f[n] = IntegerPartitions[n]; s[k_, p_] := Count[Mod[DeleteDuplicates[p], 3], k];
    Table[Count[f[n], p_ /; s[2, p] < s[0, p]], {n, 0, z}]  (* A241740 *)
    Table[Count[f[n], p_ /; s[2, p] == s[0, p]], {n, 0, z}] (* A241741 *)
    Table[Count[f[n], p_ /; s[2, p] > s[0, p]], {n, 0, z}]  (* A241742 *)

Formula

a(n) + A241741(n) + A241842(n) = A000041(n) for n >= 0.

A241741 Number of partitions p of n such that (number of numbers in p of form 3k+2) = (number of numbers in p of form 3k).

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 3, 5, 9, 11, 14, 22, 29, 36, 51, 66, 83, 107, 139, 170, 216, 273, 340, 415, 520, 635, 778, 952, 1177, 1414, 1724, 2094, 2527, 3038, 3691, 4411, 5286, 6345, 7586, 9008, 10778, 12796, 15163, 17979, 21288, 25059, 29608, 34861, 40927, 48035
Offset: 0

Views

Author

Clark Kimberling, Apr 28 2014

Keywords

Comments

Each number in p is counted once, regardless of its multiplicity.

Examples

			a(8) counts these 9 partitions:  71, 62, 53, 44, 41111, 332, 3221, 32111, 11111111.
		

Crossrefs

Programs

  • Mathematica
    z = 40; f[n_] := f[n] = IntegerPartitions[n]; s[k_, p_] := Count[Mod[DeleteDuplicates[p], 3], k];
    Table[Count[f[n], p_ /; s[2, p] < s[0, p]], {n, 0, z}]  (* A241740 *)
    Table[Count[f[n], p_ /; s[2, p] == s[0, p]], {n, 0, z}] (* A241741 *)
    Table[Count[f[n], p_ /; s[2, p] > s[0, p]], {n, 0, z}]  (* A241742 *)

Formula

a(n) + A241740(n) + A241842(n) = A000041(n) for n >= 0.

A243785 Number of unlabeled simple connected graphs with n nodes that are chordal but not integral.

Original entry on oeis.org

0, 0, 1, 4, 12, 56, 267, 1605, 11909, 109525
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 27 2014

Keywords

Crossrefs

Cf. A048192 (connected chordal graphs), A241842 (non-integral graphs).
Cf. A243786.

Formula

a(n) = A048192(n) - A243786(n).

A243274 Number of graphs with n nodes that are Hamiltonian and non-integral.

Original entry on oeis.org

1, 0, 1, 2, 1, 5, 4, 11, 12, 50
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 02 2014

Keywords

Crossrefs

Cf. A003216 (Hamiltonian graphs), A064731 (integral graphs), A241842 (non-integral graphs).

A243323 Number of simple connected graphs with n nodes that are bipartite and not integral.

Original entry on oeis.org

0, 0, 1, 2, 4, 14, 43, 179, 730, 4019
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Crossrefs

Cf. A003216 (bipartite graphs), A241842 (non-integral graphs).

A243324 Number of simple connected graphs with n nodes that are Eulerian and not integral.

Original entry on oeis.org

0, 0, 0, 0, 2, 6, 33, 180, 1773, 31006
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Crossrefs

Cf. A003049 (Eulerian graphs), A241842 (non-integral graphs).

A243325 Number of simple connected graphs with n nodes that are planar and not integral.

Original entry on oeis.org

0, 0, 1, 4, 18, 95, 642, 5962, 71876, 1052786
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Crossrefs

Cf. A003094 (planar graphs), A241842 (non-integral graphs).

A243326 Number of simple connected graphs with n nodes that are triangle-free and not integral.

Original entry on oeis.org

0, 0, 1, 2, 5, 16, 58, 264, 1380, 9818
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Crossrefs

Cf. A241842 (non-integral graphs), A024607 (triangle-free graphs).

A243327 Number of simple connected graphs with n nodes that are K_4 free and not integral.

Original entry on oeis.org

0, 0, 1, 4, 15, 77, 531, 5597, 95900, 2784034
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Comments

K_4 is the complete graph on four vertices.

Crossrefs

Cf. A241842 (non-integral graphs), A079574 (K_4-free graphs).

A243338 Number of simple connected graphs with n nodes that are trees and not integral.

Original entry on oeis.org

0, 0, 1, 2, 2, 5, 10, 23, 47, 105
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 03 2014

Keywords

Crossrefs

Cf. A241842 (non-integral graphs), A000055 (tree graphs).
Showing 1-10 of 14 results. Next