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 10 results.

A090163 Triangle T(j,k) read by rows, where T(j,K)=number of different configurations having the largest required number of moves S(j,k)=A090033(n) in optimal solutions of the j X k generalization of Sam Loyd's sliding block 15-puzzle, starting with the empty square in a corner.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 18
Offset: 1

Views

Author

Hugo Pfoertner, Nov 23 2003

Keywords

Comments

T(k,j)=T(j,k). Extension: a(10)=T(4,4)>=13, a(11)=T(5,1)=1, a(12)=T(5,2)=2.

Examples

			a(5)=T(3,2)=1 because the 3*2 sliding block puzzle has only one configuration requiring the maximum solution path length A090033(5)=21.
A090034(21)=1, see link.
		

Crossrefs

For references, links and cross-references see A087725 and A090033.

A090034 Number of configurations of the 3 X 2 variant of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 10, 12, 12, 16, 23, 25, 28, 39, 44, 40, 29, 21, 18, 12, 6, 1
Offset: 0

Views

Author

Hugo Pfoertner, Nov 23 2003

Keywords

Comments

Data from Karlemo and Östergård. See corresponding link in A087725.

Examples

			Starting with
123
45-
the most distant configuration corresponding to a(21)=1 is
45-
123 (i.e., it takes longest just to swap the two rows).
		

References

Crossrefs

Programs

A090036 Number of configurations of the 5 X 2 variant of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 6, 11, 19, 30, 44, 68, 112, 176, 271, 411, 602, 851, 1232, 1783, 2530, 3567, 4996, 6838, 9279, 12463, 16597, 21848, 28227, 35682, 44464, 54597, 65966, 78433, 91725, 104896, 116966, 126335, 131998, 133107, 128720, 119332, 106335, 91545, 75742, 60119, 45840, 33422, 23223, 15140, 9094, 5073, 2605, 1224, 528, 225, 75, 20, 2
Offset: 0

Views

Author

Hugo Pfoertner, Nov 27 2003

Keywords

Examples

			Starting from
12345
6789-
the 2 most distant configurations corresponding to a(55)=2 are
-9371 and -5321
54826.....94876
		

Crossrefs

Cf. A087725, A089473. Index of last sequence term: A090033. Other nonsquare sliding block puzzles: A090034, A090035, A090166, A090167.

Programs

A090035 Number of configurations of the 4 X 2 variant of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 6, 10, 14, 19, 28, 42, 61, 85, 119, 161, 215, 293, 396, 506, 632, 788, 985, 1194, 1414, 1664, 1884, 1999, 1958, 1770, 1463, 1076, 667, 361, 190, 88, 39, 19, 7, 1
Offset: 0

Views

Author

Hugo Pfoertner, Nov 26 2003

Keywords

Comments

Data from Karlemo, Östergård. See corresponding link in A087725.

Examples

			Starting from
1234
567-
the most distant configuration corresponding to a(36)=1 is
-721
4365
		

References

Crossrefs

Cf. A087725, A089473. Index of last sequence term: A090033. Other nonsquare sliding block puzzles: A090034, A090036, A090166, A090167.

Programs

A090167 Number of configurations of the 6 X 2 variant of the so-called "Sam Loyd" sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 6, 11, 20, 36, 60, 95, 155, 258, 426, 688, 1106, 1723, 2615, 3901, 5885, 8851, 13205, 19508, 28593, 41179, 58899, 83582, 118109, 165136, 228596, 312542, 423797, 568233, 755727, 994641, 1296097, 1667002, 2119476, 2660415, 3300586, 4038877
Offset: 0

Views

Author

Hugo Pfoertner, Nov 27 2003

Keywords

Crossrefs

Cf. A087725, A089473. Index of last sequence term: A090033. Other nonsquare sliding block puzzles: A090034, A090035, A090036, A090166.

Programs

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 22 2006

A090166 Number of configurations of the 4 X 3 variant of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 4, 9, 20, 37, 63, 122, 232, 431, 781, 1392, 2494, 4442, 7854, 13899, 24215, 41802, 71167, 119888, 198363, 323206, 515778, 811000, 1248011, 1885279, 2782396, 4009722, 5621354, 7647872, 10065800, 12760413, 15570786, 18171606, 20299876, 21587248, 21841159, 20906905, 18899357, 16058335, 12772603, 9515217, 6583181, 4242753, 2503873, 1350268, 643245, 270303, 92311, 27116, 5390, 1115, 86, 18
Offset: 0

Views

Author

Hugo Pfoertner, Nov 27 2003, Jul 07 2007

Keywords

Comments

Data from Karlemo and Östergård.

Crossrefs

Cf. A087725. Index of last sequence term: A090033. Other nonsquare sliding block puzzles: A090034, A090035, A090036, A090167.

Programs

A346736 Number of configurations of the 7 X 2 variant of the sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 6, 11, 20, 37, 67, 117, 198, 329, 557, 942, 1575, 2597, 4241, 6724, 10535, 16396, 25515, 39362, 60532, 92089, 138969, 207274, 307725, 453000, 664240, 964874, 1392975, 1992353, 2832063, 3988528, 5586275, 7756511, 10698721, 14621717, 19840724, 26676629
Offset: 0

Views

Author

Ben Whitmore, Jul 31 2021

Keywords

Comments

This sequence was originally computed by Richard Korf, but the full sequence was not included in his paper. It was later re-computed by Tomas Rokicki.

Examples

			Starting from the solved configuration
  1  2  3  4  5  6  7
  8  9 10 11 12 13
the unique configuration requiring 108 moves is
  7  6 12  4  3  9  1
    13  5 11 10  2  8
		

Crossrefs

Programs

A151944 Square array read by antidiagonals: T(m,n) = maximal number of moves required for the m X n generalization of the sliding block 15-puzzle (or fifteen-puzzle).

Original entry on oeis.org

0, 1, 1, 2, 6, 2, 3, 21, 21, 3, 4, 36, 31, 36, 4, 5, 55, 53, 53, 55, 5, 6, 80, 84, 80, 84, 80, 6, 7, 108
Offset: 1

Views

Author

Anton Kulchitsky (kulchits(AT)arsc.edu), Aug 14 2009, Aug 16 2009

Keywords

Comments

See A087725 for more about this problem and its history.

Examples

			Array begins:
.n\m...1...2...3...4...5...6...7...8...9
.----------------------------------------
.1.|...0...1...2...3...4...5...6...7...8
.2.|...1...6..21..36..55..80.108.140
.3.|...2..21..31..53..84
.4.|...3..36..53..80
.5.|...4..55..84
.6.|...5..80
.7.|...6.108
.8.|...7.140
.9.|...8
		

Crossrefs

Main diagonal: A087725. Row 2: A151943.
Cf. A090033 same as this sequence, but written as triangle.

Programs

  • Python
    # alst(), moves(), swap() in A089473
    def T(m, n):  # chr(45) is '-'
        start, shape = "".join(chr(45+i) for i in range(m*n)), (m, n)
        return len(alst(start, shape))-1
    def auptodiag(maxd):
        for d in range(1, maxd+1):
            for m in range(1, d+1):
                n = d-m+1
                print(T(m, d-m+1), end=", ")
    auptodiag(5) # Michael S. Branicky, Aug 02 2021

Extensions

Extensions from Korf's 2008 publication, with corrections, Tomas Rokicki, Aug 17 2011

A346737 Number of configurations of the 5 X 3 variant of the sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 4, 9, 21, 42, 89, 164, 349, 644, 1349, 2473, 5109, 9110, 18489, 32321, 64962, 112445, 223153, 378761, 740095, 1231589, 2364342, 3847629, 7246578, 11506172, 21233764, 32854049, 59293970, 89146163, 157015152, 228894783, 392648931, 553489877, 922382155
Offset: 0

Views

Author

Ben Whitmore, Jul 31 2021

Keywords

Comments

This sequence was originally computed by Richard Korf, but the full sequence was not included in his paper. It was later re-computed by Tomas Rokicki.

Examples

			Starting from the solved configuration
   1  2  3  4  5
   6  7  8  9 10
  11 12 13 14
the unique configuration requiring 84 moves is
   5  4  3  2  1
  10  9  8  7  6
     14 13 12 11
		

Crossrefs

Programs

A355560 Number of configurations of the 8 X 2 variant of the sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

Original entry on oeis.org

1, 2, 3, 6, 11, 20, 37, 68, 125, 227, 394, 672, 1151, 1983, 3373, 5703, 9508, 15640, 25293, 40732, 65032, 103390, 162830, 255543, 397013, 613104, 938477, 1431068, 2162964, 3255845, 4860428, 7223861, 10649867, 15628073, 22747718, 32963838, 47397514, 67825949, 96317070
Offset: 0

Views

Author

Ben Whitmore, Jul 06 2022

Keywords

Comments

This sequence was computed by Richard Korf in "Linear-time Disk-Based Implicit Graph Search" (see links), but was not included in the paper.

Examples

			Starting from the solved configuration
   1  2  3  4  5  6  7  8
   9 10 11 12 13 14 15
the unique configuration requiring 140 moves is
      8  6  5  4  3 10  1
  15  7 14 13 12 11  2  9
		

Crossrefs

Programs

Showing 1-10 of 10 results.