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.

A349187 Number of tilings of a 5 X n rectangle using n pentominoes of shapes X, Y, Z.

Original entry on oeis.org

1, 0, 0, 0, 0, 6, 6, 6, 2, 10, 86, 118, 166, 152, 372, 1394, 2450, 3866, 4946, 10160, 26380, 50770, 86522, 131632, 251150, 548436, 1075036, 1918294, 3205242, 5953962, 11962044, 23255472, 42565706, 74859582, 138078796, 266506794, 511327170, 947685504, 1713749022
Offset: 0

Views

Author

Alois P. Heinz, Nov 09 2021

Keywords

Examples

			a(5) = 6:
  ._________.     ._________.
  |_. ._._| |     | |___. ._|
  | |_| |_. |     | |_  |_| |
  | |_. ._| |     | ._| |_. |
  | ._|_| |_| (2) |_| |___| | (4)
  |_|_______|     |_______|_|      .
.
a(8) = 2:
  ._______________.
  |_. | |___. ._| |
  | | |___. |_|_. |
  | |___| |_|_. | |
  | ._| |___. | |_| (2)
  |_|_______|_|___|      .
.
		

Crossrefs

Formula

G.f.: (x^20 +6*x^19 +5*x^18 +7*x^15 +14*x^14 +7*x^13 +4*x^10 +2*x^9 +x^8 -2*x^7 -x^6 -7*x^5 -3*x^4 +1) / (11*x^20 +16*x^19 +5*x^18 +2*x^16 +33*x^15 +38*x^14 +7*x^13 +8*x^12 +20*x^11 +14*x^10 +10*x^9 -x^8 -8*x^7 -7*x^6 -13*x^5 -3*x^4 +1).

A352421 Number of tilings of a 5 X n rectangle using n pentominoes of shapes U, Y, Z.

Original entry on oeis.org

1, 0, 0, 0, 0, 4, 6, 8, 6, 8, 54, 112, 182, 232, 404, 930, 2054, 3880, 6304, 10696, 20696, 42396, 81554, 146240, 259534, 480084, 924860, 1768856, 3284468, 5992798, 11044774, 20756310, 39209398, 73369392, 135855648, 251495794, 468915328, 878762056, 1644145874
Offset: 0

Views

Author

Alois P. Heinz, Apr 25 2022

Keywords

Examples

			a(7) = 8:
  ._____________.     ._____________.     ._____________.
  |_. .___| | ._|     |_. .___| ._| |     | |_. .___| ._|
  | |_| .___| | |     | |_|_. | |_. |     | ._|_| ._| | |
  | ._|_| |___| |     | |_. | |___| |     | | ._| |___| |
  | | .___| |_. | (4) | ._| |___| |_| (2) |_| |___| |_. | (2)
  |_|_|_______|_|     |_|___|_______|     |___|_______|_|      .
.
		

Crossrefs

Formula

G.f.: (16*x^42 -16*x^41 +3*x^40 -20*x^39 -28*x^38 +28*x^37 -2*x^36 +31*x^35 +15*x^34 -38*x^33 -29*x^32 +9*x^31 +20*x^30 +69*x^29 +3*x^28 -10*x^27 +10*x^26 +2*x^25 +31*x^24 -10*x^23 -20*x^22 -41*x^21 -37*x^20 -25*x^19 +7*x^18 +8*x^17 -3*x^16 -28*x^15 -31*x^14 -9*x^13 +x^12 +2*x^11 +7*x^10 +6*x^9 -2*x^8 +4*x^7 +2*x^6 +4*x^5 +3*x^4 -1) / (2*x^45 +24*x^42 -44*x^41 -29*x^40 -42*x^39 +30*x^38 +64*x^37 +84*x^36 +79*x^35 -3*x^34 -96*x^33 -79*x^32 +61*x^31 +70*x^30 +67*x^29 -53*x^28 +82*x^26 +44*x^25 -67*x^24 -128*x^23 -110*x^22 -71*x^21 -73*x^20 -13*x^19 +39*x^18 -20*x^17 -65*x^16 -90*x^15 -29*x^14 -x^13 +5*x^12 +10*x^11 +11*x^10 +2*x^9 +4*x^8 +12*x^7 +8*x^6 +8*x^5 +3*x^4 -1).

A361250 Number of tilings of a 5 X n rectangle using n pentominoes of shapes T, N, X.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 2, 2, 8, 0, 18, 6, 16, 6, 48, 22, 74, 48, 182, 74, 306, 204, 544, 342, 1114, 826, 2038, 1546, 4144, 3126, 7452, 6470, 14538, 12542, 27824, 25994, 53398, 50244, 103288, 101306, 195756, 200120, 380310, 395802
Offset: 0

Views

Author

Alois P. Heinz, Apr 20 2023

Keywords

Examples

			a(10) = 2:
   .___________________.
   |___. |_. ._| .___| |
   |_. |___| |___|___  |
   | |_____|_| |___. |_|
   | .___| ._| |_. |___|
   |_|_____|_____|_____|  ... and its mirror.
.
a(14) = 2:
   .___________________________.
   |___. |_. ._| |_. ._| .___| |
   |_. |___| |_. ._| |___|___  |
   | |_____|_| |_| |_| |___. |_|
   | .___| ._| |_. ._| |_. |___|
   |_|_____|_____|_|_____|_____|  ... and its mirror.
.
a(16) = 2:
   ._______________________________.
   |___. |_. ._| .___|_. ._| .___| |
   |_. |___| |___| .___| |___|___  |
   | |_____|_| |___| ._|_| |___. |_|
   | .___| ._| |_____| ._| |_. |___|
   |_|_____|_____|_____|_____|_____|  ... and its mirror.
.
a(17) = 2:
   ._________________________________.
   |___. |_. ._| |___. |_. ._| .___| |
   |_. |___| |_. ._| |___| |___|___  |
   | |_____|_| |_|_. ._| |_| |___. |_|
   | .___| ._| |_. |_|_. ._| |_. |___|
   |_|_____|_____|_____|_|_____|_____|  ... and its mirror.
.
		

Crossrefs

Programs

  • Maple
    gf:= (x^14+4*x^13+2*x^11-4*x^10+x^9-3*x^8-x^6-x^4-x^3+1)/
         (x^14+6*x^13+2*x^11-6*x^10+x^9-3*x^8-x^6-x^4-x^3+1):
    a:= n-> coeff(series(gf, x, n+1), x, n):
    seq(a(n), n=0..66);

A358933 Number of tilings of a 5 X n rectangle using n pentominoes of shapes N, U, Z.

Original entry on oeis.org

1, 0, 0, 0, 2, 0, 2, 2, 4, 2, 10, 8, 14, 18, 36, 34, 66, 88, 136, 170, 292, 382, 578, 818, 1244, 1692, 2576, 3676, 5400, 7654, 11412, 16284, 23852, 34448, 50396, 72472, 106046, 153556, 223458, 323430, 471644, 683046, 993958, 1442138, 2097830, 3042314, 4424880
Offset: 0

Views

Author

Alois P. Heinz, Dec 06 2022

Keywords

Examples

			a(7) = 2:
  ._____________.    ._____________.
  | | ._. | ._. |    | ._. | ._. | |
  | |_| |_|_| |_|    |_| |_|_| |_| |
  |_. |___. |_. |    | ._| .___| ._|
  | |_| | |_| | |    | | |_| | |_| |
  |_____|_____|_|    |_|_____|_____|   .
.
		

Crossrefs

Formula

G.f.: (x-1)*(x^2 +x +1)*(4*x^26 +28*x^25 +44*x^24 +29*x^23 +x^22 -36*x^21 -49*x^20 -45*x^19 -61*x^18 +15*x^17 -7*x^16 +60*x^15 +x^14 +59*x^13 -11*x^12 +10*x^11 -37*x^10 -25*x^8 +x^7 -2*x^6 +10*x^5 +4*x^3 -1) / (8*x^32 +56*x^31 +96*x^30 +118*x^29 +118*x^28 +30*x^27 -71*x^26 -189*x^25 -298*x^24 -128*x^23 -182*x^22 +131*x^21 +52*x^20 +276*x^19 +99*x^18 +124*x^17 -30*x^16 -51*x^15 -115*x^14 -94*x^13 -43*x^12 -13*x^11 +34*x^10 +26*x^9 +35*x^8 +7*x^7 +4*x^6 -10*x^5 -2*x^4 -5*x^3 +1).
Showing 1-4 of 4 results.