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 13 results. Next

A219866 Number A(n,k) of tilings of a k X n rectangle using dominoes and straight (3 X 1) trominoes; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 4, 4, 1, 1, 1, 2, 7, 14, 7, 2, 1, 1, 2, 15, 41, 41, 15, 2, 1, 1, 3, 30, 143, 184, 143, 30, 3, 1, 1, 4, 60, 472, 1069, 1069, 472, 60, 4, 1, 1, 5, 123, 1562, 5624, 9612, 5624, 1562, 123, 5, 1
Offset: 0

Views

Author

Alois P. Heinz, Nov 30 2012

Keywords

Examples

			A(2,3) = A(3,2) = 4, because there are 4 tilings of a 3 X 2 rectangle using dominoes and straight (3 X 1) trominoes:
  .___.   .___.   .___.   .___.
  | | |   |___|   | | |   |___|
  | | |   |___|   |_|_|   | | |
  |_|_|   |___|   |___|   |_|_|
Square array A(n,k) begins:
  1,  1,  1,    1,     1,      1,        1,         1, ...
  1,  0,  1,    1,     1,      2,        2,         3, ...
  1,  1,  2,    4,     7,     15,       30,        60, ...
  1,  1,  4,   14,    41,    143,      472,      1562, ...
  1,  1,  7,   41,   184,   1069,     5624,     29907, ...
  1,  2, 15,  143,  1069,   9612,    82634,    707903, ...
  1,  2, 30,  472,  5624,  82634,  1143834,  15859323, ...
  1,  3, 60, 1562, 29907, 707903, 15859323, 354859954, ...
		

Crossrefs

Columns (or rows) k=0-10 give: A000012, A000931(n+3), A129682, A219867, A219862, A219868, A219869, A219870, A219871, A219872, A219873.
Main diagonal gives: A219874.

Programs

  • Maple
    b:= proc(n, l) option remember; local k, t;
          if max(l[])>n then 0 elif n=0 or l=[] then 1
        elif min(l[])>0 then t:=min(l[]); b(n-t, map(h->h-t, l))
        else for k do if l[k]=0 then break fi od;
             b(n, subsop(k=3, l))+ b(n, subsop(k=2, l))+
             `if`(k `if`(n>=k, b(n, [0$k]), b(k, [0$n])):
    seq(seq(A(n, d-n), n=0..d), d=0..10);
  • Mathematica
    b[n_, l_] := b[n, l] = Module[{k, t}, If [Max[l] > n, 0, If[ n == 0 || l == {}, 1, If[Min[l] > 0, t = Min[l]; b[n-t, l-t], k = Position[l, 0, 1][[1, 1]]; b[n, ReplacePart[l, k -> 3]] + b[n, ReplacePart[l, k -> 2]] + If[k < Length[l] && l[[k+1]] == 0, b[n, ReplacePart[l, {k -> 1, k+1 -> 1}]], 0] + If[k+1 < Length[l] && l[[k+1]] == 0 && l[[k+2]] == 0, b[n, ReplacePart[l, {k -> 1, k+1 -> 1, k+2 -> 1}]], 0]]]]]; a[n_, k_] := If[n >= k, b[n, Array[0&, k]], b[k, Array[0&, n]]]; Table[Table[a[n, d-n], {n, 0, d}], {d, 0, 10}] // Flatten (* Jean-François Alcover, Dec 16 2013, translated from Maple *)

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.

A219987 Number A(n,k) of tilings of a k X n rectangle using dominoes and right trominoes; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 2, 0, 1, 1, 1, 5, 5, 1, 1, 1, 0, 11, 8, 11, 0, 1, 1, 1, 24, 55, 55, 24, 1, 1, 1, 0, 53, 140, 380, 140, 53, 0, 1, 1, 1, 117, 633, 2319, 2319, 633, 117, 1, 1, 1, 0, 258, 1984, 15171, 21272, 15171, 1984, 258, 0, 1
Offset: 0

Views

Author

Alois P. Heinz, Dec 02 2012

Keywords

Examples

			A(3,3) = 8, because there are 8 tilings of a 3 X 3 rectangle using dominoes and right trominoes:
  .___._.   .___._.   .___._.   .___._.
  |___| |   |___| |   |___| |   |_. | |
  | ._|_|   | | |_|   | |___|   | |_|_|
  |_|___|   |_|___|   |_|___|   |_|___|
  ._.___.   ._.___.   ._.___.   ._.___.
  | |___|   | | ._|   | |___|   | |___|
  |___| |   |_|_| |   |_|_. |   |_| | |
  |___|_|   |___|_|   |___|_|   |___|_|
Square array A(n,k) begins:
  1,  1,   1,    1,     1,       1,         1,          1, ...
  1,  0,   1,    0,     1,       0,         1,          0, ...
  1,  1,   2,    5,    11,      24,        53,        117, ...
  1,  0,   5,    8,    55,     140,       633,       1984, ...
  1,  1,  11,   55,   380,    2319,     15171,      96139, ...
  1,  0,  24,  140,  2319,   21272,    262191,    2746048, ...
  1,  1,  53,  633, 15171,  262191,   5350806,  100578811, ...
  1,  0, 117, 1984, 96139, 2746048, 100578811, 3238675344, ...
		

Crossrefs

Columns (or rows) k=0-10 give: A000012, A059841, A052980, A165716, A165791, A219988, A219989, A219990, A219991, A219992, A219993.
Main diagonal gives: A219994.

Programs

  • Maple
    b:= proc(n, l) option remember; local k, t;
          if max(l[])>n then 0 elif n=0 or l=[] then 1
        elif min(l[])>0 then t:=min(l[]); b(n-t, map(h->h-t, l))
        else for k do if l[k]=0 then break fi od;
             b(n, subsop(k=2, l))+
             `if`(k>1 and l[k-1]=1, b(n, subsop(k=2, k-1=2, l)), 0)+
             `if`(k `if`(n>=k, b(n, [0$k]), b(k, [0$n])):
    seq(seq(A(n, d-n), n=0..d), d=0..14);
  • Mathematica
    b[n_, l_] := b[n, l] = Module[{k, t}, If[Max[l] > n, 0, If[n == 0 || l == {}, 1, If[Min[l] > 0, t = Min[l]; b[n-t, l-t], For[k = 1, True, k++, If[l[[k]] == 0, Break[]]]; b[n, ReplacePart[l, k -> 2]] + If[k > 1 && l[[k-1]] == 1, b[n, ReplacePart[l, {k -> 2, k-1 -> 2}]], 0] + If[k < Length[l] && l[[k+1]] == 1, b[n, ReplacePart[l, {k -> 2, k+1 -> 2}]], 0] + If[k < Length[l] && l[[k+1]] == 0, b[n, ReplacePart[l, {k -> 1, k+1 -> 1}]] + b[n, ReplacePart[l, {k -> 1, k+1 -> 2}]] + b[n, ReplacePart[l, {k -> 2, k+1 -> 1}]], 0] + If[k+1 < Length[l] && l[[k+1]] == 0 && l[[k+2]] == 0, b[n, ReplacePart[l, {k -> 2, k+1 -> 2, k+2 -> 2}]] + b[n, ReplacePart[l, {k -> 2, k+1 -> 2, k+2 -> 1}]], 0]]]]]; a[n_, k_] := If[n >= k, b[n, Array[0&, k]], b[k, Array[0&, n]]]; Table[Table[a[n, d-n], {n, 0, d}], {d, 0, 14}] // Flatten (* Jean-François Alcover, Dec 05 2013, translated from Alois P. Heinz's Maple program *)
  • Sage
    from sage.combinat.tiling import TilingSolver, Polyomino
    def A(n,k):
        p = Polyomino([(0,0), (0,1)])
        q = Polyomino([(0,0), (0,1), (1,0)])
        T = TilingSolver([p,q], box=[n,k], reusable=True, reflection=True)
        return T.number_of_solutions()
    # Ralf Stephan, May 21 2014

A364504 Number of tilings of an n X n square using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 0, 2, 30, 1352, 226922, 128441094, 267855152858, 1990875917805852, 52918918728713551244, 5046393600526600826576990, 1722423352379200292770200349728, 2106175531602971710801901685263906946, 9224774497259881798661234516031754156588512, 144713995908210595144464778124853904625705818728754
Offset: 0

Views

Author

Alois P. Heinz, Jul 26 2023

Keywords

Crossrefs

Main diagonal of A364457.

Formula

a(n) = A364457(n,n).

Extensions

Terms n>=4 had to be corrected as was pointed out by Martin Fuller and David Radcliffe - Alois P. Heinz, Apr 05 2025
a(13)-a(17) from David Radcliffe, Apr 07 2025

A019439 Number of ways of tiling a 2 X n rectangle with dominoes and trominoes.

Original entry on oeis.org

1, 1, 2, 6, 17, 43, 108, 280, 727, 1875, 4832, 12470, 32191, 83075, 214372, 553214, 1427673, 3684333, 9507936, 24536616, 63320419, 163407771, 421697922, 1088253936, 2808400703, 7247494517, 18703234038, 48266468208, 124558777387, 321442392689, 829529751892, 2140724511882
Offset: 0

Views

Author

N. J. A. Sloane, Oct 04 2008

Keywords

Comments

The old entry with this sequence number was a duplicate of A007737.

References

  • Jaime Rangel-Mondragon, Polyominoes and Related Families, The Mathematica Journal, 9:3 (2005), 609-640.

Crossrefs

Column k=2 of A364457.

Programs

  • Maple
    a:= n-> (Matrix([[1, 1, 0, 0, 1, 1]]). Matrix (6, (i,j)-> if i=j-1 then 1 elif j=1 then [2, 0, 3, 2, 1, -1][i] else 0 fi)^n)[1,2]: seq(a(n), n=0..30); # Alois P. Heinz, Sep 24 2009
  • Mathematica
    LinearRecurrence[{2, 0, 3, 2, 1, -1}, {1, 1, 2, 6, 17, 43}, 40] // Rest (* Jean-François Alcover, Feb 18 2016 *)

Formula

G.f.: -(x^3+x-1)/(x^6-x^5-2*x^4-3*x^3-2*x+1). - Alois P. Heinz, Sep 24 2009

Extensions

More terms from Alois P. Heinz, Sep 24 2009
a(0)=1 prepended by Alois P. Heinz, Jul 25 2023

A364155 Number of tilings of a 4 X n rectangle using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 1, 17, 145, 1352, 12688, 115958, 1075397, 9935791, 91795006, 848550447, 7841290657, 72469286374, 669744449380, 6189592846538, 57202915584686, 528655401099501, 4885709752947038, 45152583446359974, 417289539653241534, 3856491950197255757, 35640791884109598908
Offset: 0

Views

Author

Alois P. Heinz, Jul 28 2023

Keywords

Examples

			a(2) = 17:
  .___.  .___.  .___.  .___.  .___.  .___.  .___.  .___.  .___.
  | | |  |___|  |___|  | | |  |___|  |___|  | | |  | ._|  |_. |
  | | |  | | |  |___|  |_|_|  | | |  |___|  |_|_|  |_| |  | |_|
  |_|_|  | | |  |___|  |___|  |_|_|  | | |  | | |  |___|  |___|
  |___|  |_|_|  |___|  |___|  |___|  |_|_|  |_|_|  |___|  |___|
.
  .___.  .___.  .___.  .___.  .___.  .___.  .___.  .___.
  |___|  |___|  | | |  | | |  |_. |  | ._|  |_. |  | ._|
  | ._|  |_. |  | |_|  |_| |  | |_|  |_| |  | |_|  |_| |
  |_| |  | |_|  |_| |  | |_|  | | |  | | |  |_| |  | |_|
  |___|  |___|  |___|  |___|  |_|_|  |_|_|  |___|  |___|  .
		

Crossrefs

Column k=4 of A364457.

Formula

G.f.: -(x^42 -3*x^41 +2*x^40 -27*x^39 +20*x^38 -47*x^37 +679*x^36 -807*x^35 +971*x^34 -3668*x^33 +4911*x^32 -17380*x^31 +41345*x^30 -21439*x^29 +1694*x^28 -117750*x^27 +184140*x^26 -41964*x^25 +99138*x^24 -180813*x^23 +70242*x^22 -240711*x^21 +162785*x^20 +46241*x^19 +117557*x^18 -67141*x^17 +25483*x^16 -51680*x^15 -25799*x^14 +7385*x^13 +5758*x^12 -1195*x^11 +1461*x^10 +2940*x^9 -1582*x^8 +1207*x^7 +281*x^6 -199*x^5 -31*x^4 -67*x^3 -22*x^2 -3*x +1) / (x^45 -4*x^44 -15*x^43 -10*x^42 +187*x^41 -211*x^40 +112*x^39 +653*x^38 +3519*x^37 -17169*x^36 +12166*x^35 -10114*x^34 +56406*x^33 -139986*x^32 +336502*x^31 -459720*x^30 +309573*x^29 -410529*x^28 +1231995*x^27 -1670818*x^26 +883613*x^25 -1050005*x^24 +1530359*x^23 -1044441*x^22 +1664063*x^21 -1162643*x^20 +189181*x^19 -701476*x^18 +413937*x^17 -243226*x^16 +257069*x^15 +69116*x^14 -27774*x^13 -9998*x^12 +5208*x^11 -12030*x^10 -3922*x^9 +3364*x^8 -2794*x^7 -335*x^6 +452*x^5 +99*x^4 +109*x^3 +35*x^2 +4*x -1).

Extensions

Terms n>=4 had to be corrected as was pointed out by Martin Fuller and David Radcliffe - Alois P. Heinz, Apr 05 2025

A364460 Number of tilings of a 3 X n rectangle using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 1, 6, 30, 145, 733, 3540, 17300, 84479, 411963, 2011408, 9816506, 47911847, 233851991, 1141365064, 5570761346, 27189615925, 132706261547, 647709321582, 3161321546320, 15429691961077, 75308819284819, 367565220881250, 1794002281279416, 8756117243124305, 42736617464745197
Offset: 0

Views

Author

Alois P. Heinz, Jul 25 2023

Keywords

Examples

			a(2) = 6:
  .___.   .___.   .___.   .___.   .___.   .___.
  | | |   |___|   | | |   |___|   | ._|   |_. |
  | | |   |___|   |_|_|   | | |   |_| |   | |_|
  |_|_|   |___|   |___|   |_|_|   |___|   |___|  .
		

Crossrefs

Column k=3 of A364457.
Cf. A133872.

Formula

G.f.: -(x^15 +2*x^14 +4*x^13 -5*x^12 -9*x^11 -18*x^10 +16*x^9 +5*x^8 +8*x^7 -10*x^6 +13*x^5 -6*x^4 +7*x^3 +3*x^2 +2*x -1) / (x^18 +3*x^17 -x^16 -18*x^15 -8*x^14 -38*x^13 +24*x^12 +76*x^11 +125*x^10 -35*x^9 -48*x^8 -69*x^7 -18*x^6 -53*x^5 -13*x^3 -6*x^2 -3*x +1).
a(n) mod 2 = A133872(n).

A364556 Number of tilings of a 5 X n rectangle using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 2, 43, 733, 12688, 226922, 3927233, 68846551, 1204757533, 21062468900, 368521437132, 6445706387345, 112749099291387, 1972235696214897, 34498222540798726, 603446574091501719, 10555520988321750183, 184637793249606497610, 3229696298942838688793, 56494043669663414794810
Offset: 0

Views

Author

Alois P. Heinz, Jul 28 2023

Keywords

Examples

			a(1) = 2:
    ._.   ._.
    | |   | |
    | |   |_|
    |_|   | |
    | |   | |
    |_|   |_|   .
		

Crossrefs

Column k=5 of A364457.

Extensions

Terms n>=4 had to be corrected as was pointed out by Martin Fuller and David Radcliffe - Alois P. Heinz, Apr 05 2025

A364616 Number of tilings of a 6 X n rectangle using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 2, 108, 3540, 115958, 3927233, 128441094, 4263997124, 141186107223, 4671227129777, 154679198549385, 5119908497703914, 169488865440883593, 5610718094136694973, 185732776135043052107, 6148417237267189975927, 203533740825252409802705, 6737670699036802296758849
Offset: 0

Views

Author

Alois P. Heinz, Jul 29 2023

Keywords

Examples

			a(1) = 2:
    ._.   ._.
    | |   | |
    |_|   | |
    | |   |_|
    |_|   | |
    | |   | |
    |_|   |_|   .
		

Crossrefs

Column k=6 of A364457.

Extensions

Terms n>=4 had to be corrected as was pointed out by Martin Fuller and David Radcliffe - Alois P. Heinz, Apr 05 2025

A364617 Number of tilings of a 7 X n rectangle using dominoes and trominoes (of any shape).

Original entry on oeis.org

1, 3, 280, 17300, 1075397, 68846551, 4263997124, 267855152858, 16785795917908, 1051116421516975, 65871551452359237, 4126577980480405170, 258538236543240798654, 16197912784372244064693, 1014813990592495583029006, 63579642939479330198729573, 3983348112669764700919476270
Offset: 0

Views

Author

Alois P. Heinz, Jul 29 2023

Keywords

Examples

			a(1) = 3:
    ._.   ._.   ._.
    | |   | |   | |
    |_|   |_|   | |
    | |   | |   |_|
    |_|   | |   | |
    | |   |_|   |_|
    | |   | |   | |
    |_|   |_|   |_|   .
		

Crossrefs

Column k=7 of A364457.

Extensions

Terms n>=4 had to be corrected as was pointed out by Martin Fuller and David Radcliffe - Alois P. Heinz, Apr 05 2025
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