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.

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A263816 T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having index change (+-,+-) 0,0 0,1 0,2 or 1,0.

Original entry on oeis.org

9, 82, 32, 572, 948, 121, 3682, 18776, 11305, 450, 25001, 333429, 643905, 134028, 1681, 170946, 6425985, 31916832, 21876416, 1590733, 6272, 1157993, 124854432, 1746531193, 3019386508, 744805993, 18875976, 23409, 7844192, 2392853088
Offset: 1

Views

Author

R. H. Hardin, Oct 27 2015

Keywords

Comments

Table starts
......9.........82..........572...........3682...........25001.........170946
.....32........948........18776.........333429.........6425985......124854432
....121......11305.......643905.......31916832......1746531193....96761217077
....450.....134028.....21876416.....3019386508....469723808009.74221751084228
...1681....1590733....744805993...286407546797.126619013196417
...6272...18875976..25345430544.27150876030959
..23409..223995034.862592912860
..87362.2658056430
.326041

Examples

			Some solutions for n=2 k=4
..0..1..3..2..4....0..3..2..8..4....0..6..2..8..4....0..3..2..8..4
..5..6..7..8..9....6..1.12..9..7....7..1..9..3.14....5..1..9..6..7
.12.10.11.14.13....5.10.13.11.14....5.11.10.13.12...12.10.11.14.13
		

Crossrefs

Column 1 is A006253(n+1).

Formula

Empirical for column k:
k=1: a(n) = 3*a(n-1) +3*a(n-2) -a(n-3)
k=2: a(n) = 10*a(n-1) +23*a(n-2) -10*a(n-3) -a(n-4)
k=3: [order 15]
k=4: [order 82]
Empirical for row n:
n=1: [linear recurrence of order 26]

A233308 Number A(n,k) of tilings of a k X k X n box using k*n bricks of shape k X 1 X 1; square array A(n,k), n>=0, k>=1, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 9, 1, 1, 2, 4, 32, 1, 1, 2, 4, 21, 121, 1, 1, 2, 4, 8, 92, 450, 1, 1, 2, 4, 8, 45, 320, 1681, 1, 1, 2, 4, 8, 16, 248, 1213, 6272, 1, 1, 2, 4, 8, 16, 93, 1032, 4822, 23409, 1, 1, 2, 4, 8, 16, 32, 668, 3524, 18556, 87362, 1, 1, 2, 4, 8, 16, 32, 189, 3440, 13173, 70929, 326041, 1
Offset: 0

Views

Author

Alois P. Heinz, Dec 07 2013

Keywords

Examples

			Square array A(n,k) begins:
  1,     1,     1,     1,     1,     1, ...
  1,     2,     2,     2,     2,     2, ...
  1,     9,     4,     4,     4,     4, ...
  1,    32,    21,     8,     8,     8, ...
  1,   121,    92,    45,    16,    16, ...
  1,   450,   320,   248,    93,    32, ...
  1,  1681,  1213,  1032,   668,   189, ...
  1,  6272,  4822,  3524,  3440,  1832, ...
  1, 23409, 18556, 13173, 13728, 11976, ...
		

Crossrefs

Columns k=1-6 give: A000012, A006253, A233289, A233291, A233294, A233424.
Diagonals include: A000079, A068156.

Programs

  • Maple
    b:= proc(n, l) option remember; local d, t, k; d:= isqrt(nops(l));
          if max(l[])>n then 0 elif n=0 then 1
        elif min(l[])>0 then t:=min(l[]); b(n-t, map(x->x-t, l))
        else for k while l[k]>0 do od; b(n, subsop(k=d, l))+
             `if`(irem(k,d)=1 and {seq(l[k+j], j=1..d-1)}={0},
             b(n, [seq(`if`(h-k=0, 1, l[h]), h=1..nops(l))]), 0)+
             `if`(k<=d and {seq(l[k+d*j], j=1..d-1)}={0},
             b(n, [seq(`if`(irem(h-k, d)=0, 1, l[h]), h=1..nops(l))]), 0)
          fi
        end:
    A:= (n, k)-> `if`(k>n, 2^n, b(n, [0$k^2])):
    seq(seq(A(n, 1+d-n), n=0..d), d=0..11);
  • Mathematica
    b[n_, l_] := b[n, l] = Module[{d, t, k}, d= Sqrt[Length[l]]; Which[ Max[l]>n, 0, n==0, 1, Min[l]>0, t=Min[l]; b[n-t, l-t], True, k=Position[l, 0, 1][[1, 1]]; b[n, ReplacePart[l, k->d]]+ If[Mod[k, d]==1 && Union[ Table[ l[[k+j]], {j, 1, d-1}]] == {0}, b[n, Table[ If [h-k=0, 1, l[[h]] ], {h, 1, Length[l]}]], 0]+ If[k <= d && Union[ Table[ l[[k+d*j]], {j, 1, d-1}]] == {0}, b[n, Table[ If[ Mod[h-k, d] == 0, 1, l[[h]] ], {h, 1, Length[l]}]], 0] ] ]; a[n_, k_]:= If[k>n, 2^n, b[n, Array[0&, k^2]]]; Table[Table[a[n, 1+d-n], {n, 0, d}], {d, 0, 11}] // Flatten (* Jean-François Alcover, Dec 13 2013, translated from Maple *)

Formula

A(n,k) = 2^n = A000079(n) for k>n.
A(n,n) = A068156(n) for n>1.

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.

A233289 Number of tilings of a 3 X 3 X n box using 3n bricks of shape 3 X 1 X 1.

Original entry on oeis.org

1, 2, 4, 21, 92, 320, 1213, 4822, 18556, 70929, 273808, 1057020, 4069737, 15676666, 60424640, 232846801, 897164316, 3457096532, 13321674833, 51332757274, 197801848744, 762200458321, 2937024077340, 11317358546188, 43609682555721, 168043191679374
Offset: 0

Views

Author

Alois P. Heinz, Dec 06 2013

Keywords

Comments

This is a variant of the Jenga game (see link).

Crossrefs

Column k=3 of A233308.

Programs

  • Maple
    gf:= (x^7-x^6+x^5-x^4+4*x^3+2*x^2+x-1)/(-x^10+x^9
         -3*x^8+4*x^7-7*x^6-11*x^5+2*x^4+13*x^3+3*x-1):
    a:= n-> coeff(series(gf, x, n+1), x, n):
    seq(a(n), n=0..30);

Formula

G.f.: (x^7 -x^6 +x^5 -x^4 +4*x^3 +2*x^2 +x -1) / (-x^10 +x^9 -3*x^8 +4*x^7 -7*x^6 -11*x^5 +2*x^4 +13*x^3 +3*x -1).

A028452 Number of perfect matchings in graph P_{3} X P_{3} X P_{2n}.

Original entry on oeis.org

1, 229, 117805, 64647289, 35669566217, 19690797527709, 10870506600976757, 6001202979497804657, 3313042830624031354513, 1829008840116358153050197, 1009728374600381843221483965, 557433823481589253332775648233, 307738670509229621147710358375321
Offset: 0

Views

Author

Keywords

Comments

Also the number of tilings of a 3 x 3 x 2n box with 1 x 1 x 2 bricks. - Johan de Ruiter, Jul 15 2012

Crossrefs

Formula

From Johan de Ruiter, Jul 15 2012: (Start)
a(n) = 679a(n-1) -76177a(n-2) +3519127a(n-3) -85911555a(n-4) +1235863045a(n-5) -11123194131a(n-6) +65256474997a(n-7) -257866595482a(n-8) +705239311926a(n-9) -1363115167354a(n-10) +1888426032982a(n-11) -1888426032982a(n-12) +1363115167354a(n-13) -705239311926a(n-14) +257866595482a(n-15) -65256474997a(n-16) +11123194131a(n-17) -1235863045a(n-18) +85911555a(n-19) -3519127a(n-20) +76177a(n-21) -679a(n-22) +a(n-23).
G.f.: (x^18 -446x^17 +36701x^16 -1267416x^15 +22828288x^14 -235207768x^13 +1443564488x^12 -5338083112x^11 +11818867674x^10 -15460884436x^9 +11818867674x^8 -5338083112x^7 +1443564488x^6 -235207768x^5 +22828288x^4 -1267416x^3 +36701x^2 -446x +1)/(-x^19 +675x^18 -73471x^17 +3221189x^16 -72583272x^15 +925908264x^14 -6971103216x^13 +31523058272x^12 -86171526770x^11 +142604534086x^10 -142604534086x^9 +86171526770x^8 -31523058272x^7 +6971103216x^6 -925908264x^5 +72583272x^4 -3221189x^3 +73471x^2 -675x +1).
(End)

A233291 Number of tilings of a 4 X 4 X n box using 4n bricks of shape 4 X 1 X 1.

Original entry on oeis.org

1, 2, 4, 8, 45, 248, 1032, 3524, 13173, 54274, 228712, 917992, 3608665, 14286188, 57438652, 231343468, 926921081, 3700936774, 14793198332, 59241396140, 237333611629, 950127617692, 3801974385964, 15215432779936, 60907523900693, 243826775063490, 976008753961184
Offset: 0

Views

Author

Alois P. Heinz, Dec 06 2013

Keywords

Crossrefs

Column k=4 of A233308.

Formula

G.f.: (x^31 -x^30 -x^29 -3*x^28 -5*x^27 +8*x^26 +3*x^25 -39*x^24 +48*x^23 +34*x^22 -11*x^21 +112*x^20 -63*x^19 -34*x^18 +166*x^17 -188*x^16 -174*x^15 +151*x^14 -251*x^13 +57*x^12 +104*x^11 +171*x^10 -69*x^9 -90*x^8 -30*x^7 -61*x^6 +20*x^5 +31*x^4 +4*x^3 +4*x^2 +x -1) / (-x^35 +x^34 +x^33 +5*x^32 +4*x^31 -11*x^30 -10*x^29 +54*x^28 -65*x^27 -48*x^26 -48*x^25 -195*x^24 +231*x^23 -78*x^22 -473*x^21 +794*x^20 +447*x^19 -981*x^18 +1285*x^17 +395*x^16 -720*x^15 -202*x^14 +640*x^13 +567*x^12 -232*x^11 +638*x^10 -169*x^9 -233*x^8 -256*x^7 -97*x^6 +29*x^5 +52*x^4 -4*x^3 +2*x^2 +3*x -1).

A233294 Number of tilings of a 5 X 5 X n box using 5n bricks of shape 5 X 1 X 1.

Original entry on oeis.org

1, 2, 4, 8, 16, 93, 668, 3440, 13728, 46252, 172577, 739002, 3417464, 15550336, 65956764, 271247405, 1119519052, 4726308568, 20348072952, 87598217268, 373660404281, 1581318625634, 6680851858676, 28326586367464, 120536842633616, 513461699313993
Offset: 0

Views

Author

Alois P. Heinz, Dec 06 2013

Keywords

Crossrefs

Column k=5 of A233308.

Formula

G.f.: see link above.

A359886 Number of 3-dimensional tilings of a 2 X 2 X n box using 2 X 2 X 1 plates and trominos (three 1 X 1 X 1 cubes).

Original entry on oeis.org

1, 1, 3, 49, 231, 789, 4771, 27225, 122799, 607469, 3255979, 16253649, 80098519, 409480005, 2079921395, 10411734921, 52523676351, 266059774429, 1341128940795, 6758479842689, 34138205819239, 172324729379509, 869131661400259, 4386075013348025, 22138673661637327
Offset: 0

Views

Author

Gerhard Kirchner, Jan 20 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 6.

Examples

			a(3) = 49.
The number of tilings only using plates is A001045(3) = 5.
The number of tilings only using trominos is A359885(1) = 44.
These terms are to be added as, for n=3, there is no tiling using both tiles.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{2, 1, 58, 72, 32, -128}, {1, 1, 3, 49, 231, 789}, 30] (* Paolo Xausa, Jun 24 2024 *)
  • Maxima
    /* See link "Maxima code". */

Formula

G.f.: (1 - x - 16*x^3) / (1 - 2*x - x^2 - 58*x^3 - 72*x^4 - 32*x^5 + 128*x^6).
Recurrence 1:
a(n) = a(n-1) + 3*c(n-2) + 2*a(n-2) + 4*c(n-3) + 8*a(n-3),
c(n) = 12*a(n-1) + c(n-1) + 16*a(n-2) + 16*c(n-3),
with a(n),c(n) <= 0 for n <= 0 except for a(0)=1.
Recurrence 2:
a(n) = 2*a(n-1) + a(n-2) + 58*a(n-3) + 72*a(n-4) + 32*a(n-5) - 128*a(n-6) for n >= 6.
For n < 6, recurrence 1 can be used.

A028454 Number of perfect matchings in graph P_{4} X P_{4} X P_{n}.

Original entry on oeis.org

1, 36, 32000, 10885344, 5051532105, 2132137503232, 932814464901633, 403325499406267520, 175220727982196365632, 75996591204223021534740, 32983893365927357595999561, 14312021563707748863632803328, 6210770058902782255142931025577
Offset: 0

Views

Author

Keywords

Crossrefs

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