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

A222763 Number of n X 2 0..1 arrays with exactly floor(nX2/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

1, 0, 3, 4, 20, 48, 175, 512, 1719, 5400, 17776, 57420, 188656, 617176, 2033175, 6697744, 22139780, 73262232, 242931321, 806516560, 2681475048, 8925158440, 29740390672, 99196158144, 331163178475, 1106489052968, 3699881730900, 12380449027324, 41454579098852
Offset: 0

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Author

R. H. Hardin, Mar 05 2013

Keywords

Comments

From Gus Wiseman, Oct 05 2022: (Start)
Conjecture: Also the number of integer compositions of 2n + 1 with the same length as reverse-alternating sum. Here, the reverse-alternating sum of a sequence (y_1,...,y_k) is Sum_i (-1)^i y_i. For example, the a(4) = 20 compositions are:
(135) (234) (333) (432) (531)
(11115) (21114) (31113) (41112) (51111)
(11214) (21213) (31212) (41211)
(11313) (21312) (31311)
(11412) (21411)
(11511)
This is the odd-indexed version of A357182, and the corresponding unordered count (partitions) is A357488.
(End)

Examples

			All solutions for n=3
..0..1....0..0....0..0....0..0
..0..0....0..0....0..1....1..0
..0..0....1..0....0..0....0..0
		

Crossrefs

Column k = 2 of A222769.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n<3, [1, 0, 3][n+1],
          (4*(n-1)*(74*n^2-153*n+73)*a(n-1) +8*(2*n-3)*
          (74*n^2-153*n+70)*a(n-2) -2*(37*n-21)*(2*n-5)*
          (n-1)*a(n-3))/(5*(37*n-58)*n*(n-1)))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Sep 24 2024

Formula

a(n) = A105422(2n,n). - Alois P. Heinz, Sep 24 2024
a(n) = (n+1)*A046736(n+2). - Mark van Hoeij, Nov 29 2024

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 24 2024

A222764 Number of nX3 0..1 arrays with exactly floor(nX3/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

0, 4, 13, 96, 301, 2242, 7575, 55958, 196442, 1448568, 5188656, 38338122, 138866688, 1029494580, 3754449699, 27929878716, 102325331440, 763577070328, 2806916894109, 21001612120424, 77405327921654, 580452846750048
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Column 3 of A222769

Examples

			Some solutions for n=3
..0..0..0....0..0..0....0..0..0....0..1..0....0..1..0....0..0..0....0..1..1
..0..0..0....0..0..0....1..1..1....0..0..0....1..1..1....0..0..0....1..1..1
..0..1..0....1..1..1....1..1..1....0..0..0....1..1..1....1..0..1....1..1..0
		

A222765 Number of nX4 0..1 arrays with exactly floor(nX4/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

3, 11, 66, 465, 3431, 25772, 196185, 1508369, 11685222, 91068653, 713197411, 5607868082, 44244333098, 350085423285, 2776997948510, 22076166728109, 175834747565068, 1402892278684566, 11209941707509701, 89696333927946099
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Column 4 of A222769

Examples

			Some solutions for n=3
..0..0..0..1....0..0..0..0....0..0..0..1....0..1..0..1....0..0..0..0
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..0....0..0..0..1
..0..0..1..1....1..0..1..1....0..1..0..0....0..0..0..0....0..1..0..1
		

A222766 Number of nX5 0..1 arrays with exactly floor(nX5/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

4, 18, 158, 2608, 19766, 333978, 2645385, 45830457, 370518626, 6504289924, 53224723750, 942396671062, 7774316625479, 138492173604656, 1149166452333809, 20564313304270211, 171388475477573948, 3077759439903425070
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Column 5 of A222769

Examples

			Some solutions for n=3
..0..1..0..0..1....0..1..0..1..1....0..0..0..0..0....0..0..0..1..1
..0..0..0..0..0....1..1..1..1..1....0..0..0..1..0....0..0..0..1..1
..0..0..0..0..0....1..1..1..1..0....0..1..0..0..0....0..0..0..1..0
		

A222767 Number of nX6 0..1 arrays with exactly floor(nX6/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

4, 73, 934, 15077, 256546, 4479721, 79612578, 1432512703, 26011740182, 475591230143, 8742929996332, 161434491485598, 2991759796200596, 55616288265939185, 1036645299974444114, 19366819201445345894
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Column 6 of A222769

Examples

			Some solutions for n=3
..0..1..0..0..0..0....0..1..1..1..0..0....0..1..1..1..0..0....0..0..0..0..1..0
..1..1..0..0..0..0....1..1..1..1..0..0....1..1..0..0..0..0....0..0..0..0..1..1
..1..1..1..0..0..0....1..1..1..1..0..1....0..1..0..0..0..0....0..1..1..1..1..1
		

A222768 Number of nX7 0..1 arrays with exactly floor(nX7/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

5, 152, 2446, 89811, 1570588, 62017670, 1139211468, 46316300783, 872037778022, 36016907441620, 687733392122744, 28680675666813436, 552611942013475560, 23197864298620002960, 449800925803708450740, 18972874575715876051106
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Column 7 of A222769

Examples

			Some solutions for n=3
..0..0..0..1..0..1..1....0..0..0..1..1..1..0....0..0..1..1..1..0..0
..0..0..0..0..1..0..0....1..1..1..1..1..1..1....0..0..1..0..0..0..0
..0..0..0..0..0..0..0....0..1..1..1..1..1..1....0..0..1..0..0..0..0
		

A222770 Number of 2Xn 0..1 arrays with exactly floor(2Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

0, 3, 4, 11, 18, 73, 152, 470, 1022, 3361, 7840, 23386, 57626, 172387, 434280, 1257025, 3275034, 9399647, 24776572, 70325187, 188540168, 531573662, 1436226680, 4032772569, 10987025446, 30742228871, 84180549328, 235159618106
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Row 2 of A222769

Examples

			All solutions for n=3
..0..0..0....0..0..0....0..0..1....0..0..1
..0..1..1....1..0..0....1..1..1....0..0..0
		

A222771 Number of 3Xn 0..1 arrays with exactly floor(3Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

0, 4, 13, 66, 158, 934, 2446, 14567, 39972, 240130, 673665, 4073862, 11545686, 70212506, 200446066, 1224207384, 3512430906, 21526789216, 62001340484, 381049009426, 1100824791540, 6780941436208, 19637801359798, 121196222602133
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Row 3 of A222769

Examples

			Some solutions for n=3
..0..0..0....0..0..0....0..1..0....0..1..1....0..0..1....0..0..0....0..0..0
..0..0..0....0..0..0....0..0..0....0..1..1....1..0..0....0..0..1....0..0..1
..0..1..0....1..1..1....0..0..0....1..1..1....0..0..0....1..0..0....0..0..1
		

A222772 Number of 4Xn 0..1 arrays with exactly floor(4Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

0, 20, 96, 465, 2608, 15077, 89811, 544302, 3349328, 20823047, 130535918, 823585242, 5221057054, 33231082276, 212180118775, 1358528423728, 8718262087314, 56062919553225, 361148981248207, 2330144611056838
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Row 4 of A222769

Examples

			Some solutions for n=3
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..1....0..0..0
..0..1..0....1..1..1....0..0..1....0..0..0....0..1..0....0..0..0....0..0..1
..1..0..0....0..1..1....0..0..0....0..1..0....0..0..0....0..1..1....0..0..1
..0..0..0....1..1..1....0..1..1....0..1..1....0..0..0....1..1..1....0..1..1
		

A222773 Number of 5Xn 0..1 arrays with exactly floor(5Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..1 order.

Original entry on oeis.org

0, 48, 301, 3431, 19766, 256546, 1570588, 21526008, 136549058, 1916013454, 12429454430, 176824724591, 1163475046332, 16694274193142, 110869265032135, 1600019787081011, 10694449471174787, 154977656102006006
Offset: 1

Views

Author

R. H. Hardin Mar 05 2013

Keywords

Comments

Row 5 of A222769

Examples

			Some solutions for n=3
..0..0..0....0..1..1....0..0..0....0..0..0....0..1..0....0..0..0....0..0..0
..1..1..1....1..1..1....0..0..0....0..1..1....0..0..0....0..0..0....0..0..0
..1..1..1....0..1..1....1..0..0....0..1..1....0..0..0....0..0..1....0..1..1
..1..1..1....1..1..1....0..0..0....1..1..1....0..0..1....0..1..1....1..1..0
..1..0..0....1..1..0....1..0..1....1..1..0....0..0..0....0..1..0....1..0..0
		
Showing 1-10 of 13 results. Next