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 1-4 of 4 results.

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

A233427 Number A(n,k) of tilings of a k X n rectangle using pentominoes 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, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 5, 0, 0, 5, 0, 1, 1, 0, 0, 56, 0, 56, 0, 0, 1, 1, 0, 0, 0, 501, 501, 0, 0, 0, 1, 1, 0, 0, 0, 0, 4006, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 27950, 27950, 0, 0, 0, 1, 1, 1, 0, 45, 0, 0, 214689, 0, 214689, 0, 0, 45, 0, 1
Offset: 0

Views

Author

Alois P. Heinz, Dec 09 2013

Keywords

Examples

			A(5,2) = A(2,5) = 5:
  ._________. ._________. ._________. ._________. ._________.
  |_________| | ._____| | | |_____. | |   ._|   | |   |_.   |
  |_________| |_|_______| |_______|_| |___|_____| |_____|___|.
Square array A(n,k) begins:
  1, 1,  1,    1,      1,         1,          1, ...
  1, 0,  0,    0,      0,         1,          0, ...
  1, 0,  0,    0,      0,         5,          0, ...
  1, 0,  0,    0,      0,        56,          0, ...
  1, 0,  0,    0,      0,       501,          0, ...
  1, 1,  5,   56,    501,      4006,      27950, ...
  1, 0,  0,    0,      0,     27950,          0, ...
  1, 0,  0,    0,      0,    214689,          0, ...
  1, 0,  0,    0,      0,   1696781,          0, ...
  1, 0,  0,    0,      0,  13205354,          0, ...
  1, 1, 45, 7670, 890989, 101698212, 7845888732, ...
  ...
		

Crossrefs

Formula

A(n,k) = 0 <=> n*k mod 5 > 0.

A247740 Total number of T shapes in all tilings of a 5 X n rectangle with pentominoes of any shape.

Original entry on oeis.org

0, 0, 0, 6, 66, 772, 6760, 60122, 552930, 4887052, 42365416, 361418592, 3063883318, 25819450218, 215875963118, 1793852851690, 14833014554258, 122147248758898, 1002084660185318, 8192705916505028, 66777880125812344, 542833111487459532, 4401913323626254612, 35616479684643020150
Offset: 0

Views

Author

Alois P. Heinz, Sep 23 2014

Keywords

Crossrefs

Formula

a(n) = Sum_{k>0} k * A247707(n,k).

A247771 Number of tilings of a 5 X n rectangle using n pentominoes of any but the T shape.

Original entry on oeis.org

1, 1, 5, 50, 437, 3270, 21720, 160593, 1209537, 8999307, 66054288, 485082083, 3583263174, 26469863097, 195317239597, 1440271919247, 10624063817149, 78389991175482, 578363501074881, 4266856868607953, 31478045125433448, 232231064765922254, 1713315860292710073
Offset: 0

Views

Author

Alois P. Heinz, Sep 23 2014

Keywords

Crossrefs

Column k=0 of A247707.
Showing 1-4 of 4 results.