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 12 results. Next

A174249 Number of tilings of a 5 X n rectangle with n pentominoes of any shape.

Original entry on oeis.org

1, 1, 5, 56, 501, 4006, 27950, 214689, 1696781, 13205354, 101698212, 782267786, 6048166230, 46799177380, 361683136647, 2793722300087, 21583392631817, 166790059833039, 1288885349447958, 9959188643348952, 76953117224941654, 594617039453764617, 4594660583890506956
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

Formula

a(n) ~ c * d^n, where d =
7.727036840800092392128639105511391434436212757335030092041375597587338371937..., c =
0.13364973920881772493778581621701653927538155984099992758656160782495174... (1/d is the root of the denominator, see g.f.). - Vaclav Kotesovec, May 19 2015

Extensions

a(0) prepended, a(11)-a(22) from Alois P. Heinz, Dec 05 2013

A174248 Number of tilings of a 4 X n rectangle with n tetrominoes of any shape.

Original entry on oeis.org

1, 1, 4, 23, 117, 454, 2003, 9157, 40899, 179399, 796558, 3546996, 15747348, 69834517, 310058192, 1376868145, 6112247118, 27132236455, 120453362938, 534754586459, 2373975139658, 10538953415410, 46786795734201, 207705902269424, 922089495910044, 4093525019450760
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

Formula

G.f.: -(x^31 +3*x^30 -2*x^29 -7*x^28 -25*x^27 -78*x^26 +23*x^25 +116*x^24 +217*x^23 +604*x^22 -21*x^21 -556*x^20 -649*x^19 -1621*x^18 -175*x^17 +727*x^16 +523*x^15 +1707*x^14 +236*x^13 -470*x^12 -143*x^11 -749*x^10 -133*x^9 +166*x^8 +15*x^7 +126*x^6 +27*x^5 -23*x^4 -x^3 -6*x^2 -x +1) / (x^35 +3*x^34 -3*x^33 -13*x^32 -50*x^31 -123*x^30 +39*x^29 +225*x^28 +659*x^27 +1476*x^26 +60*x^25 -1102*x^24 -2600*x^23 -6047*x^22 -489*x^21 +2786*x^20 +3210*x^19 +9566*x^18 +1102*x^17 -3349*x^16 -1620*x^15 -6885*x^14 -1053*x^13 +1970*x^12 +414*x^11 +2258*x^10 +469*x^9 -548*x^8 -76*x^7 -290*x^6 -77*x^5 +54*x^4 +8*x^3 +8*x^2 +2*x -1). - Alois P. Heinz, Nov 26 2013

Extensions

a(0) inserted, a(11)-a(22) from Alois P. Heinz, May 07 2013
a(23)-a(25) from Alois P. Heinz, Nov 26 2013

A233320 Number A(n,k) of tilings of a k X n rectangle using trominoes of any shape; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 3, 3, 0, 1, 1, 0, 0, 10, 0, 0, 1, 1, 1, 0, 23, 23, 0, 1, 1, 1, 0, 11, 62, 0, 62, 11, 0, 1, 1, 0, 0, 170, 0, 0, 170, 0, 0, 1, 1, 1, 0, 441, 939, 0, 939, 441, 0, 1, 1, 1, 0, 41, 1173, 0, 8342, 8342, 0, 1173, 41, 0, 1
Offset: 0

Views

Author

Alois P. Heinz, Dec 07 2013

Keywords

Comments

Every row and column satisfies a linear recurrence. - Peter Kagey, Jul 17 2019

Examples

			Square array A(n,k) begins:
  1, 1,  1,    1,   1,    1,       1, ...
  1, 0,  0,    1,   0,    0,       1, ...
  1, 0,  0,    3,   0,    0,      11, ...
  1, 1,  3,   10,  23,   62,     170, ...
  1, 0,  0,   23,   0,    0,     939, ...
  1, 0,  0,   62,   0,    0,    8342, ...
  1, 1, 11,  170, 939, 8342,   80092, ...
  1, 0,  0,  441,   0,    0,  614581, ...
  1, 0,  0, 1173,   0,    0, 5271923, ...
		

Crossrefs

Formula

A(n,k) = 0 <=> n*k mod 3 > 0.

A215826 Number of ways in which a 9 X n grid can be tiled with trominoes.

Original entry on oeis.org

1, 1, 41, 3127, 41813, 1269900, 45832761, 1064557805, 30860212081, 928789262080, 25020222581494, 714819627084057, 20574308184277971, 576115800837801057, 16381774291037991059, 466431115279461257920, 13190758349044182698371, 374524994697062170913555
Offset: 0

Views

Author

V. Raman, Aug 23 2012

Keywords

Crossrefs

Cf. A215827 (number of memoizations needed to calculate a(n)), A134438, A233290, A269664.
Column k=9 of A233320.

A233290 Number of tilings of a 6 X n rectangle with 2n trominoes of any shape.

Original entry on oeis.org

1, 1, 11, 170, 939, 8342, 80092, 614581, 5271923, 45832761, 379419508, 3223419241, 27438555522, 231096250072, 1958024834151, 16593169804557, 140295718998907, 1187830239559588, 10056816580083721, 85104482994177208, 720410915948382970, 6098207777286812381
Offset: 0

Views

Author

Alois P. Heinz, Dec 06 2013

Keywords

Examples

			a(2) = 11:
.___. .___. .___. .___. .___. .___. .___. .___. .___. .___. .___.
| | | | ._| |_. | | ._| | | | |_. | | | | |_. | | ._| | ._| |_. |
| | | |_| | | |_| |_| | | | | | |_| | | | | |_| |_| | |_| | | |_|
|_|_| |___| |___| |___| |_|_| |___| |_|_| |___| |___| | | | | | |
| | | | ._| |_. | | | | | ._| | | | |_. | | ._| |_. | | |_| |_| |
| | | |_| | | |_| | | | |_| | | | | | |_| |_| | | |_| |_| | | |_|
|_|_| |___| |___| |_|_| |___| |_|_| |___| |___| |___| |___| |___|.
		

Crossrefs

Column k=6 of A233320.

A174250 Number of tilings of a 6 X n rectangle with n hexominoes of any shape.

Original entry on oeis.org

1, 1, 6, 132, 2369, 33344, 451206, 5850115, 81459922, 1144259389, 15946621499
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

A174251 Number of tilings of a 7 X n rectangle with n heptominoes of any shape.

Original entry on oeis.org

1, 1, 7, 259, 9525, 270827, 6633399, 158753814, 3825111851, 96608374284, 2446223788303
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

A174252 Number of tilings of an 8 X n rectangle with n octominoes of any shape.

Original entry on oeis.org

1, 1, 8, 546, 39731, 2152050, 99697633, 4292655082, 187497290034, 8378760802160, 385296986628990
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

A174253 Number of tilings of a 9 X n rectangle with n nonominoes of any shape.

Original entry on oeis.org

1, 1, 9, 1095, 145415, 15661597, 1418159011, 112976454947, 8812020831683, 706152947468301, 58015563977931125
Offset: 0

Views

Author

Bob Harris (me13013(AT)gmail.com), Mar 13 2010

Keywords

Crossrefs

A269664 Number of tilings of a 12 X n rectangle with 4n trominoes of any shape.

Original entry on oeis.org

1, 1, 153, 58234, 1895145, 198253934, 27438555522, 1949314526229, 193553900967497, 20574308184277971, 1830607857363940042, 178792253082742021463, 17735061025562799941630, 1679378707647721857218932, 163105210594579645492072521, 15894545877032388610890500803
Offset: 0

Views

Author

Alois P. Heinz, Mar 02 2016

Keywords

Crossrefs

Column k=12 of A233320.
Showing 1-10 of 12 results. Next