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 1-9 of 9 results.

A287428 Array read by antidiagonals: T(m,n) is the number of matchings in the stacked prism graph C_m X P_n.

Original entry on oeis.org

1, 2, 3, 3, 12, 4, 5, 47, 32, 7, 8, 185, 228, 108, 11, 13, 728, 1655, 1511, 342, 18, 21, 2865, 11978, 21497, 9213, 1104, 29, 34, 11275, 86731, 305184, 253880, 57536, 3544, 47, 55, 44372, 627960, 4334009, 6974078, 3079253, 356863, 11396, 76
Offset: 1

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Author

Andrew Howroyd, May 25 2017

Keywords

Comments

Row 1 is the number of matchings in P_n and row 2 is the number of matchings in G X P_n where G is a double edge. These choices give the best fit with the column linear recurrences.

Examples

			Table starts:
======================================================================
m\n|  1    2      3        4          5            6              7
---|------------------------------------------------------------------
1  |  1    2      3        5          8           13             21 ...
2  |  3   12     47      185        728         2865          11275 ...
3  |  4   32    228     1655      11978        86731         627960 ...
4  |  7  108   1511    21497     305184      4334009       61545775 ...
5  | 11  342   9213   253880    6974078    191668283     5267252351 ...
6  | 18 1104  57536  3079253  164206124   8761336545   467431319920 ...
7  | 29 3544 356863 37071837 3834744194 396924243197 41080815923665 ...
...
		

Crossrefs

Columns 2..3 are A102080, A102090.
Cf. A028420 (P_m X P_n), A270246 (C_m X C_n), A270227 (K_m X K_n).

A360064 Number of 3-dimensional tilings of a 2 X 2 X n box using 1 X 1 X 1 cubes and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 5, 89, 1177, 16873, 237977, 3366793, 47599097, 673035625, 9516252633, 134553882441, 1902506043833, 26900227288361, 380352114739609, 5377937177440009, 76040613721296249, 1075165950495479017, 15202163218500810073, 214948926180739194569
Offset: 0

Views

Author

Gerhard Kirchner, Jan 30 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 8.

Examples

			4 rotations:
   ___ ___     ___ ___
  |   |   |   |   |   | (cross sections)
  |   |___|   |___|___|
  |       |   |   |   |
  |_______|   |___|___| a(1) = 4 + 1 = 5.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{13, 20, -64, 112, 224, -128}, {1, 5, 89, 1177, 16873, 237977}, 25] (* Paolo Xausa, Oct 02 2024 *)

Formula

G.f.: (1 - 8*x + 4*x^2 - 16*x^3) / (1 - 13*x - 20*x^2 + 64*x^3 - 112*x^4 - 224*x^5 + 128*x^6).
Recurrence 1:
a(n) = 5*a(n-1) + 2*b(n-1) + c(n-1) + d(n-1) + e(n-1) + 8*a(n-2) + 4*b(n-2) + c(n-2) + 2*d(n-2),
b(n) = 8*a(n-1) + 4*b(n-1) + 2*c(n-1),
c(n) = 20*a(n-1) + 6*b(n-1) + 4*c(n-1) + 4*d(n-1) + 2*e(n-1),
d(n) = 4*a(n-1), e(n) = 16*a(n-1) + 4*b(n-1),
with a(n), b(n), c(n), d(n), e(n) = 0 for n <= 0 except for a(0)=1.
Recurrence 2:
a(n) = 13*a(n-1) + 20*a(n-2) - 64*a(n-3) + 112*a(n-4) + 224*a(n-5) - 128*a(n-6) for n >= 6. For n < 6, recurrence 1 can be used.

A360065 Number of 3-dimensional tilings of a 2 X 2 X n box using 2 X 1 X 1 dominos and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 2, 45, 412, 4705, 50374, 549109, 5955544, 64683649, 702259786, 7625147293, 82791470836, 898931464993, 9760376329678, 105975828745957, 1150659965697328, 12493588746237697, 135652375422278290, 1472880803124594061, 15992184812239930060, 173639288800074705121
Offset: 0

Views

Author

Gerhard Kirchner, Jan 30 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 9.

Examples

			a(2)=45
1) Two parallel trominos and one domino: There are 3 middle axes of the 2 X 2 cube with 4 rotation images each: 12 images.
       ___             ___         ___ ___
     /__ /|          /   /|      /__ /   /|
   /__ /| |___     /__ /  |    /__ /__ /  |
  |   | |/__ /|   |   |  /    |   |   |  /|
  |   |/__ /| | + |___|/   =  |   |___|/| |
  |       | |/                |       | |/
  |_______|/                  |_______|/
2) Two "linked" trominos and one domino: 12 rotation images and, as there is no symmetry plane, 12 mirror images: 24 images.
       ___                       ___         ___ ___
     /   /|                    /   /|      /   /   /|
   /__ /  |      _______     /__ /  |    /__ /__ /  |
  |   |  /     /__     /|   |   |  /    |   |   |  /|
  |   | |  +  |  /__ /  | + |___|/   =  |   |___|/  |
  |   | |     |_|   |  /                |   |   |  /
  |___|/        |___|/                  |___|___|/
3) Using only dominos: A006253(2)=9 ways, Sum: a(2) = 12 + 24 + 9 = 45.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{7, 42, 6, -81, 27}, {1, 2, 45, 412, 4705}, 25] (* Paolo Xausa, Oct 02 2024 *)

Formula

G.f.: (1 - 5*x - 11*x^2 + 7*x^3) / (1 - 7*x - 42*x^2 - 6*x^3 + 81*x^4 - 27*x^5).
Recurrence 1:
a(n) = 2*a(n-1) + b(n-1) + c(n-1) + 13*a(n-2) + 2*b(n-2) + c(n-2) + 2*d(n-2),
b(n) = 12*a(n-1) + 2*b(n-1) + 2*c(n-1) + e(n-1),
c(n) = 16*a(n-1) + 6*b(n-1) + c(n-1) + 2*e(n-1),
d(n) = 4*a(n-1) + 2*b(n-1) + d(n-1),
e(n) = 16*a(n-1) + 5*b(n-1) + 2*c(n-1) + 2*d(n-1),
with a(n), b(n), c(n), d(n), e(n) = 0 for n <= 0 except for a(0)=1.
Recurrence 2:
a(n) = 7*a(n-1) + 42*a(n-2) + 6*a(n-3) - 81*a(n-4) + 27*a(n-5) for n >= 5.
For n < 5, recurrence 1 can be used.

A045310 Number of matchings in n-cube.

Original entry on oeis.org

1, 2, 7, 108, 41025, 13803794944, 7174574164703330195841
Offset: 0

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Author

Keywords

Comments

a(4) = A033532(1), a(5) = A033532(2).
a(3) = A033516(2) = A033535(2). - Alois P. Heinz, Dec 09 2013
Equivalently, the number of decompositions of an n-dimensional cube of size 2 into (zero or more) unit cubes (1 X 1 X ... X 1) and "dominoes" (2 X 1 X 1 X ... X 1). - Hugo van der Sanden, Nov 30 2016

Examples

			From _Max Alekseyev_, Nov 16 2009: (Start)
E.g., for n=2, we have
1 matching of size 0 (i.e., the empty matching)
4 matchings of size 1 (i.e., an edge)
2 matchings of size 2 (that are the perfect matchings).
So a(2) = 1 + 4 + 2 = 7, whereas A005271(2) = 2. (End)
		

Crossrefs

For perfect matchings see A005271.
For matching polynomials, see A192437, A302235.
Cf. A033532.

Programs

  • C
    /* See Links section. */
  • Perl
    # See Links section.
    

A360066 Number of 3-dimensional tilings of a 2 X 2 X n box using 1 X 1 X 1 cubes, 2 X 1 X 1 dominos and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 11, 444, 13311, 422617, 13265660, 417336617, 13123557903, 412719195520, 12979269602143, 408175860119021, 12836425011761592, 403683424226081169, 12695147020245034099, 399240466722076292612, 12555423726269799691295, 394846409914451855949249
Offset: 0

Views

Author

Gerhard Kirchner, Jan 30 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 10.

Crossrefs

Programs

Formula

G.f.: (1 - 15*x - 18*x^2 - 23*x^3 + 7*x^4) / (1 - 26*x - 176*x^2 + 146*x^3 + 14*x^4 + 140*x^5 - 27*x^6).
Recurrence 1:
a(n) = 11*a(n-1) + 4*b(n-1) + 2*c(n-1) + d(n-1) + e(n-1) + 29*a(n-2) + 6*b(n-2) + c(n-2) + 2*d(n-2),
b(n) = 32*a(n-1) + 9*b(n-1) + 4*c(n-1) + 2*d(n-1) + e(n-1),
c(n) = 52*a(n-1) + 14*b(n-1) + 5*c(n-1) + 4*d(n-1) + 2*e(n-1),
d(n) = 14*a(n-1) + 3*b(n-1) + d(n-1),
e(n) = 48*a(n-1) + 11*b(n-1) + 2*c(n-1) + 2*d(n-1),
with a(n), b(n), c(n), d(n), e(n) = 0 for n <= 0 except for a(0)=1.
Recurrence 2:
a(n) = 26*a(n-1) + 176*a(n-2) - 146*a(n-3) - 14*a(n-4) - 140*a(n-5) + 27*a(n-6) for n >= 6. For n < 6, recurrence 1 can be used.

A360575 Number of 3-dimensional tilings of a 2 X 2 X n box using 1 X 1 X 1 cubes, 2 X 1 X 1 dominos and 2 X 2 X 1 plates.

Original entry on oeis.org

1, 8, 153, 2470, 41571, 693850, 11602579, 193942076, 3242104149, 54196828452, 905988148597, 15145052657186, 253174020910071, 4232212575080006, 70748267813548207, 1182671546039152712, 19770264765434877913, 330491902143708738464
Offset: 0

Views

Author

Gerhard Kirchner, Feb 12 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 11.

Crossrefs

Formula

G.f.: (1-8*x+4*x^2+11*x^3-6*x^4) / (1-16*x-21*x^2+157*x^3-100*x^4-65*x^5+42*x^6).
Recurrence 1:
a(n) = 8*a(n-1) + 3*b(n-1) + 2*c(n-1) + d(n-1) + e(n-1) + 7*a(n-2)
b(n) = 12*a(n-1) + 5*b(n-1) + 2*c(n-1) + 2*d(n-1) + e(n-1)
c(n) = 16*a(n-1) + 4*b(n-1) + 2*c(n-1)
d(n) = 2*a(n-1) + b(n-1) + d(n-1)
e(n) = 12*a(n-1) + 3*b(n-1)
with a(n),b(n),c(n),d(n),e(n)= 0 for n<=0 except for a(0)=1.
Recurrence 2:
a(n)=16*a(n-1) + 21*a(n-2) - 157*a(n-3) + 100*a(n-4) + 65*a(n-5) - 42*a(n-6)
for n>=6. For n<6, recurrence 1 can be used.

A360576 Number of 3-dimensional tilings of a 2 X 2 X n box using 1 X 1 X 1 cubes, 2 X 2 X 1 plates and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 6, 122, 1768, 28844, 457592, 7318760, 116806896, 1865305376, 29782666544, 475549098160, 7593154541264, 121241257906000, 1935879286697296, 30910512661708432, 493553365105565264, 7880649886335326608, 125831666350680625104
Offset: 0

Views

Author

Gerhard Kirchner, Feb 12 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 12.

Crossrefs

Formula

G.f.: (1-9*x+4*x^2-16*x^3) / (1-15*x-28*x^2+214*x^3-192*x^4-384*x^5+128*x^6).
Recurrence 1:
a(n) = 8*a(n-1) + 3*b(n-1) + 2*c(n-1) + d(n-1) + e(n-1) + 7*a(n-2)
b(n) = 12*a(n-1) + 5*b(n-1) + 2*c(n-1) + 2*d(n-1) + e(n-1)
c(n) = 16*a(n-1) + 4*b(n-1) + 2*c(n-1)
d(n) = 2*a(n-1) + b(n-1) + d(n-1)
e(n) = 12*a(n-1) + 3*b(n-1)
with a(n),b(n),c(n),d(n),e(n)= 0 for n<=0 except for a(0)=1.
Recurrence 2:
a(n)=15*a(n-1) + 28*a(n-2) - 214*a(n-3) + 192*a(n-4) + 384*a(n-5) - 128*a(n-6)
for n>=6. For n<6, recurrence 1 can be used.

A360577 Number of 3-dimensional tilings of a 2 X 2 X n box using 2 X 2 X 1 plates, 2 X 1 X 1 dominos and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 3, 60, 657, 8311, 101284, 1246049, 15292819, 187803572, 2305968393, 28315208039, 347681742812, 4269186204201, 52421329940803, 643681521419708, 7903765218510353, 97050331862075975, 1191681006432895780, 14632650860374551265, 179674317212728197891, 2206220907971874345652
Offset: 0

Views

Author

Gerhard Kirchner, Feb 12 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 13.

Crossrefs

Formula

G.f.: (1-5*x-15*x^2-3*x^3+10*x^4) / (1-8*x-51*x^2-27*x^3+96*x^4+43*x^5-66*x^6).
Recurrence 1:
a(n) = 3*a(n-1) + b(n-1) + c(n-1) + 19*a(n-2) + 4*b(n-2) + c(n-2) + 2*d(n-2)
b(n) = 12*a(n-1) + 2*b(n-1) + 2*c(n-1) + e(n-1)
c(n) = 20*a(n-1) + 6*b(n-1) + 2*c(n-1) + 2*e(n-1)
d(n) = 4*a(n-1) + 2*b(n-1) + d(n-1)
e(n) = 24*a(n-1) + 7*b(n-1) + 2*c(n-1) + 2*d(n-1)
with a(n),b(n),c(n),d(n),e(n)= 0 for n<=0 except for a(0)=1.
Recurrence 2:
a(n)=8*a(n-1) + 51*a(n-2) + 27*a(n-3) - 96*a(n-4) - 43*a(n-5) + 66*a(n-6)
for n>=6. For n<6, recurrence 1 can be used.

A360644 Number of 3-dimensional tilings of a 2 X 2 X n box using 1 X 1 X 1 cubes, 2 X 1 X 1 dominos, 2 X 2 X 1 plates and trominos (L-shaped connection of 3 cubes).

Original entry on oeis.org

1, 12, 513, 16194, 547543, 18234354, 609298887, 20344385080, 679408772089, 22688284005780, 757662377924917, 25301659203704234, 844933359518672599, 28216027727373068302, 942256839186226313727, 31466085716246304261600, 1050790517091131646143477
Offset: 0

Views

Author

Gerhard Kirchner, Feb 15 2023

Keywords

Comments

Recurrence 1 is derived in A359884, "3d-tilings of a 2 X 2 X n box" as a special case of a more general tiling problem: III, example 14.

Crossrefs

Formula

G.f.: (1-16*x-18*x^2-13*x^3+10*x^4) / (1-28*x-195*x^2+497*x^3-30*x^4+79*x^5-66*x^6)
Recurrence 1:
a(n) = 12*a(n-1) + 4*b(n-1) + 2*c(n-1) + d(n-1) + e(n-1) + 43*a(n-2) + 8*b(n-2) + c(n-2) + 2*d(n-2)
b(n) = 32*a(n-1) + 9*b(n-1) + 4*c(n-1) + 2*d(n-1) + e(n-1)
c(n) = 60*a(n-1) + 16*b(n-1) + 6*c(n-1) + 4*d(n-1) + 2*e(n-1)
d(n) = 14*a(n-1) + 3*b(n-1) + d(n-1)
e(n) = 64*a(n-1) + 13*b(n-1) + 2*c(n-1) + 2*d(n-1)
with a(n),b(n),c(n),d(n),e(n)= 0 for n<=0 except for a(0)=1.
Recurrence 2:
a(n)=28*a(n-1) + 195*a(n-2) - 497*a(n-3) + 30*a(n-4) - 79*a(n-5) + 66*a(n-6)
for n>=6. For n<6, recurrence 1 can be used.
Showing 1-9 of 9 results.