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.

A342864 Irregular table read by rows: T(n,k) is the number of permutations in S_n that have exactly k occurrences of the pattern 1432. 0 <= k <= A100354(n).

Original entry on oeis.org

1, 1, 2, 6, 23, 1, 103, 11, 5, 0, 1, 513, 87, 68, 17, 18, 10, 0, 4, 2, 0, 1, 2761, 625, 626, 268, 274, 138, 112, 58, 51, 44, 31, 9, 15, 8, 12, 0, 5, 0, 0, 0, 3, 15767, 4378, 5038, 2781, 3060, 1697, 1817, 1036, 964, 773, 656, 450, 379, 320, 285, 148, 237, 97, 98, 55, 68, 61, 23, 30, 30, 13, 30, 0, 0, 0, 16, 0, 10, 0, 0, 1, 0, 0, 0, 0, 2
Offset: 0

Views

Author

Peter Kagey, Mar 26 2021

Keywords

Comments

Equivalently the table for the patterns 2341, 3214, and 4123.
First column is A005802.

Examples

			Table begins:
  n\k|       0        1        2        3        4        5        6
  ---+-------------------------------------------------------------------
   0 |       1;
   1 |       1;
   2 |       2;
   3 |       6;
   4 |      23,       1;
   5 |     103,      11,       5,       0,       1;
   6 |     513,      87,      68,      17,      18,      10,       0, ...
   7 |    2761,     625,     626,     268,     274,     138,     112, ...
   8 |   15767,    4378,    5038,    2781,    3060,    1697,    1817, ...
   9 |   94359,   30671,   38541,   24731,   28881,   17943,   21193, ...
  10 |  586590,  216883,  289785,  205853,  251051,  170941,  211942, ...
  11 | 3763290, 1552588, 2172387, 1663964, 2096207, 1535129, 1954751, ...
		

Crossrefs

Analogous for other patterns: A008302 (12), A138159 (321), A263771 (312), A342840 (1342), A342860 (2413), A342861 (1324), A342862 (2143), A342863 (1243), A342865 (1234).

A342646 Maximal number of 4213 patterns in a permutation of 1,2,...,n.

Original entry on oeis.org

0, 0, 0, 0, 1, 3, 6, 13, 24, 40, 62, 96, 138, 192, 264, 354
Offset: 0

Views

Author

Peter Kagey, Mar 20 2021

Keywords

Comments

Equivalently the maximal number of 1342, 2431, and 3124 patterns.

Examples

			For n = 7, a(7) = 13 because the permutation 7532146 has 13 instances of the pattern 4213, namely: 7536, 7526, 7516, 7546, 7324, 7326, 7314, 7316, 7214, 7216, 5324, 5314, and 5214.
Moreover, all other permutations in S_7 have 13 or fewer instances of this pattern.
		

Crossrefs

Analogous for other patterns: A000292 (123), A000332 (1234), A061061 (132), A100354 (1432).

Extensions

a(10)-a(12) from Rob Pratt
a(13)-a(15) from Bert Dobbelaere, Mar 26 2021

A100355 Maximal number of 15432 patterns in a permutation of 1,2,...,n.

Original entry on oeis.org

0, 0, 0, 0, 1, 5, 15, 35, 70, 140, 252, 420, 660, 990, 1485, 2145, 3003, 4095, 5460, 7280, 9520, 12240, 15504, 19381, 24226, 29926, 36576, 44276, 53135, 63761, 75905, 89705, 105305, 122865, 143340, 166272, 191850, 220270, 251755, 287715, 327395, 371043
Offset: 1

Views

Author

Vincent Vatter, Nov 18 2004

Keywords

Examples

			a(24) = 19381; the 24-permutation with the most copies of 15432 is 1, 5, 4, 3, 2, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6.
		

References

  • W. Stromquist, Packing layered posets into posets, manuscript.

Crossrefs

Formula

a(n) = max(a(k) + k*choose(n-k, 4), 1 <= k < n)

A100356 Maximal number of 165432 patterns in a permutation of 1,2,...,n.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 6, 21, 56, 126, 252, 504, 924, 1584, 2574, 4004, 6006, 9009, 13104, 18564, 25704, 34884, 46512, 62016, 81396, 105336, 134596, 170016, 212520, 265650, 328900, 403650, 491400, 593775, 712531, 855037, 1019467, 1208257, 1424017
Offset: 1

Views

Author

Vincent Vatter, Nov 18 2004

Keywords

Examples

			a(12) = 502; the 12-permutation with the most copies of 165432 is 2, 1, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3.
		

References

  • W. Stromquist, Packing layered posets into posets, manuscript.

Crossrefs

Formula

a(n) = max(a(k) + k*choose(n-k, 5), 1 <= k < n)

A342853 Maximal number of 1324 patterns in a permutation of 1,2,...,n.

Original entry on oeis.org

0, 0, 0, 0, 1, 3, 6, 13, 24, 42, 68, 106, 153, 217, 300
Offset: 0

Views

Author

Peter Kagey, Mar 25 2021

Keywords

Comments

Equivalently the maximal number of 4231 patterns in a permutation of 1,2,...,n.

Examples

			For n = 5, the permutation 14325 has a(5) = 3 subsequences with the same relative order as 1324: 1435, 1425, and 1325.
All other permutations in S_5 have 3 or fewer such subsequences.
		

Crossrefs

Analogous for other patterns: A000292 (123), A000332 (1234), A061061 (132), A100354 (1432), A342646 (4213), A342854 (2413).

Extensions

a(11) from Code Golf Stack Exchange link added by Peter Kagey, Mar 25 2021
a(12)-a(14) from Hugo Pfoertner, Mar 26 2021

A342854 Maximal number of 2413 patterns in a permutation of 1,2,...,n.

Original entry on oeis.org

0, 0, 0, 0, 1, 2, 5, 9, 17, 26, 41, 60, 88, 120, 163, 213
Offset: 0

Views

Author

Peter Kagey, Mar 25 2021

Keywords

Comments

Equivalently the maximal number of 3142 patterns in a permutation of 1,2,...,n.

Examples

			For n = 6, the permutation 246135 has a(6) = 5 subsequences with the same relative order as 2413: 2413, 2613, 2615, 4615, and 4635.
All other permutations in S_6 have 5 or fewer such subsequences.
		

Crossrefs

Analogous for other patterns: A000292 (123), A000332 (1234), A061061 (132), A100354 (1432), A342646 (4213), A342853 (1324).
Cf. A342860.

Extensions

a(11)-a(14) from Hugo Pfoertner, Mar 26 2021
a(15) from Hugo Pfoertner, Apr 05 2021
Showing 1-6 of 6 results.