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 11 results. Next

A266464 Number of n X 2 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 29, 42, 59, 80, 106, 137, 174, 217, 267, 324, 389, 462, 544, 635, 736, 847, 969, 1102, 1247, 1404, 1574, 1757, 1954, 2165, 2391, 2632, 2889, 3162, 3452, 3759, 4084, 4427, 4789, 5170, 5571, 5992, 6434, 6897, 7382, 7889, 8419, 8972, 9549, 10150
Offset: 0

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Examples

			Some solutions for n=4:
..0..0....0..0....0..1....0..0....0..1....0..0....1..1....0..1....0..0....0..1
..0..0....0..0....0..1....1..1....1..0....0..0....1..1....1..0....0..0....1..0
..0..1....0..0....1..0....1..1....1..1....1..1....1..1....1..0....0..0....1..0
..1..0....1..1....1..0....1..1....1..1....1..1....1..1....1..1....0..0....1..0
		

Crossrefs

Column 2 of A266470.
Partial sums of A033638.

Programs

  • Maple
    a:= proc(n) option remember;
         `if`(n<0, 0, 1+a(n-1)+floor(n^2/4))
        end:
    seq(a(n), n=0..100);  # Alois P. Heinz, Dec 27 2023

Formula

a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 3*a(n-4) -a(n-5).
From Colin Barker, Mar 21 2018: (Start)
G.f.: (x^3-x+1)/((x+1)*(x-1)^4).
a(n) = (2*n^3 + 3*n^2 + 22*n + 24) / 24 for n even.
a(n) = (2*n^3 + 3*n^2 + 22*n + 21) / 24 for n odd.
(End)

Extensions

a(0)=1 prepended by Alois P. Heinz, Dec 27 2023

A266465 Number of n X 3 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

2, 5, 12, 29, 67, 147, 303, 590, 1090, 1922, 3253, 5311, 8400, 12918, 19377, 28425, 40873, 57722, 80196, 109776, 148240, 197703, 260666, 340063, 439318, 562401, 713894, 899055, 1123895, 1395251, 1720873, 2109508, 2570998, 3116374, 3757967
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Examples

			Some solutions for n=4:
..0..0..0....0..0..0....0..1..1....0..1..1....0..0..1....0..0..1....0..0..1
..0..0..0....0..1..1....1..0..1....1..0..1....0..1..0....1..1..0....0..1..0
..0..0..0....1..0..0....1..1..0....1..1..0....1..0..0....1..1..1....1..0..0
..0..0..0....1..1..1....1..1..0....1..1..1....1..1..0....1..1..1....1..1..1
		

Crossrefs

Column 3 of A266470.

Formula

Empirical: a(n) = 5*a(n-1) - 8*a(n-2) + a(n-3) + 9*a(n-4) - 6*a(n-5) - 6*a(n-7) + 9*a(n-8) + a(n-9) - 8*a(n-10) + 5*a(n-11) - a(n-12).
Empirical g.f.: x*(2 - 5*x + 3*x^2 + 7*x^3 - 5*x^4 - x^5 - 3*x^6 + 7*x^7 - 7*x^9 + 5*x^10 - x^11) / ((1 - x)^8*(1 + x)^2*(1 + x + x^2)). - Colin Barker, Jan 10 2019

A266466 Number of nX4 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

2, 6, 19, 66, 232, 794, 2574, 7797, 22058, 58469, 146027, 345578, 779240, 1682359, 3492869, 6999952, 13585959, 25610002, 47004982, 84187248, 147421139, 252829908, 425319569, 702767285, 1141951244, 1826839569, 2880058656, 4478585700
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Column 4 of A266470.

Examples

			Some solutions for n=4
..0..1..1..1....0..0..0..1....0..0..0..0....0..0..1..1....0..1..1..1
..1..0..0..1....0..0..0..1....0..1..1..1....0..1..0..0....0..1..1..1
..1..1..1..0....1..1..1..0....1..0..0..0....1..0..0..0....1..0..0..0
..1..1..1..1....1..1..1..0....1..0..0..0....1..1..0..0....1..0..0..0
		

Crossrefs

Cf. A266470.

A266467 Number of nX5 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

2, 7, 28, 137, 735, 4074, 22128, 113677, 544142, 2417707, 9991874, 38585111, 139969744, 479482160, 1558677189, 4829461991, 14318767180, 40765225229, 111787710303, 296081929163, 759290568963, 1889449601320, 4571408444209
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Column 5 of A266470.

Examples

			Some solutions for n=4
..0..0..0..0..0....0..0..0..1..1....0..0..0..0..0....0..1..1..1..1
..0..0..0..0..1....0..1..1..0..0....0..0..1..1..1....1..0..0..0..0
..0..0..1..1..0....1..0..0..0..0....1..1..0..0..0....1..0..1..1..1
..1..1..0..0..0....1..0..0..0..0....1..1..1..1..1....1..1..0..0..0
		

Crossrefs

Cf. A266470.

A266471 Number of 4 X n binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

5, 12, 29, 66, 137, 261, 463, 775, 1237, 1898, 2817, 4064, 5721, 7883, 10659, 14173, 18565, 23992, 30629, 38670, 48329, 59841, 73463, 89475, 108181, 129910, 155017, 183884, 216921, 254567, 297291, 345593, 400005, 461092, 529453, 605722, 690569
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Examples

			Some solutions for n=4:
..0..0..0..0....0..0..0..0....0..1..1..1....0..0..0..0....0..0..1..1
..0..0..0..0....0..0..0..0....1..0..0..0....0..0..1..1....0..1..0..0
..1..1..1..1....0..0..0..0....1..0..1..1....1..1..0..0....1..0..0..0
..1..1..1..1....1..1..1..1....1..1..0..0....1..1..1..1....1..1..1..1
		

Crossrefs

Row 4 of A266470.

Formula

Empirical: a(n) = (1/120)*n^5 + (1/24)*n^4 + (17/24)*n^3 - (25/24)*n^2 + (257/60)*n + 1.
Conjectures from Colin Barker, Jan 10 2019: (Start)
G.f.: x*(5 - 18*x + 32*x^2 - 28*x^3 + 11*x^4 - x^5) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)

A266472 Number of 5 X n binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

6, 19, 67, 232, 735, 2090, 5371, 12645, 27639, 56726, 110334, 204903, 365538, 629531, 1050952, 1706538, 2703140, 4187021, 6355333, 9470138, 13875377, 20017232, 28468369, 39956595, 55398509, 75938776, 102995704, 138313857, 184024492
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Examples

			Some solutions for n=4:
..0..0..1..1....0..1..1..1....0..0..0..1....0..0..0..1....0..1..1..1
..0..1..0..0....1..0..0..0....0..1..1..1....0..1..1..0....1..0..0..1
..1..0..0..0....1..0..0..1....1..0..1..0....0..1..1..0....1..0..1..0
..1..0..0..0....1..0..1..0....1..1..0..0....1..0..0..0....1..1..0..0
..1..0..0..0....1..1..0..0....1..1..1..0....1..0..0..1....1..1..1..1
		

Crossrefs

Row 5 of A266470.

Formula

Empirical: a(n) = (1/181440)*n^9 + (1/8064)*n^8 + (29/15120)*n^7 + (13/960)*n^6 + (301/8640)*n^5 + (101/384)*n^4 - (34619/90720)*n^3 + (37531/10080)*n^2 - (4171/2520)*n + 4.
Conjectures from Colin Barker, Jan 10 2019: (Start)
G.f.: x*(6 - 41*x + 147*x^2 - 303*x^3 + 410*x^4 - 382*x^5 + 248*x^6 - 109*x^7 + 30*x^8 - 4*x^9) / (1 - x)^10.
a(n) = 10*a(n-1) - 45*a(n-2) + 120*a(n-3) - 210*a(n-4) + 252*a(n-5) - 210*a(n-6) + 120*a(n-7) - 45*a(n-8) + 10*a(n-9) - a(n-10) for n>10.
(End)

A266473 Number of 6Xn binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

7, 29, 147, 794, 4074, 18808, 77320, 285494, 959672, 2975483, 8605341, 23428725, 60497931, 149066593, 352233950, 801471439, 1762213254, 3755124007, 7774777259, 15675004492, 30833594755, 59276323572, 111542905766, 205731574732
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Row 6 of A266470.

Examples

			Some solutions for n=4
..0..0..1..1....0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1
..0..1..0..0....1..1..1..0....0..0..1..0....0..1..1..1....0..0..1..0
..0..1..0..1....1..1..1..0....0..0..1..0....1..0..1..1....0..1..1..0
..1..0..0..1....1..1..1..1....0..1..0..0....1..1..0..0....1..0..0..0
..1..0..1..0....1..1..1..1....1..0..0..1....1..1..0..0....1..0..0..0
..1..1..1..0....1..1..1..1....1..1..0..0....1..1..1..1....1..1..0..1
		

Crossrefs

Cf. A266470.

Formula

Empirical: a(n) = (1/121645100408832000)*n^19 + (1/914624815104000)*n^18 + (37/533531142144000)*n^17 + (89/31384184832000)*n^16 + (1039/12553673932800)*n^15 + (116807/62768369664000)*n^14 + (3153461/94152554496000)*n^13 + (511019/1034643456000)*n^12 + (57504877/9656672256000)*n^11 + (48689987/877879296000)*n^10 + (475429693/1207084032000)*n^9 + (2471183497/1207084032000)*n^8 + (117295069721/23538138624000)*n^7 + (79279038437/3362591232000)*n^6 + (2282457077/12108096000)*n^5 - (6773798653/40864824000)*n^4 + (20107095509/9648639000)*n^3 - (10497092849/7718911200)*n^2 + (607842269/116396280)*n + 1

A266474 Number of 7Xn binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

8, 42, 303, 2574, 22128, 175180, 1231170, 7652503, 42460424, 212971589, 977395362, 4147719749, 16420984346, 61103700814, 215040758842, 719522481940, 2299243641848, 7043942786447, 20758083457211, 59015575393057
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Row 7 of A266470.

Examples

			Some solutions for n=4
..0..0..0..1....0..0..1..1....0..0..1..1....0..0..0..1....0..1..1..1
..0..0..0..1....0..1..1..1....0..1..0..0....0..0..1..0....1..0..1..1
..0..1..1..0....1..0..0..0....1..0..0..1....0..1..0..0....1..0..1..1
..1..0..0..1....1..1..0..0....1..0..0..1....1..0..0..0....1..0..1..1
..1..1..1..0....1..1..0..1....1..1..0..0....1..1..1..1....1..1..0..0
..1..1..1..0....1..1..1..0....1..1..1..0....1..1..1..1....1..1..0..0
..1..1..1..1....1..1..1..1....1..1..1..0....1..1..1..1....1..1..0..0
		

Crossrefs

Cf. A266470.

Formula

Empirical polynomial of degree 34 (see link above)

A266463 Number of n X n binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

2, 4, 12, 66, 735, 18808, 1231170, 223521350, 119000455681, 193166954325425, 983670413713595700
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Diagonal of A266470.

Examples

			Some solutions for n=4
..0..0..0..0....0..0..1..1....0..0..0..1....0..0..0..0....0..1..1..1
..0..0..1..1....1..1..0..1....0..1..1..0....0..0..0..1....1..0..0..1
..1..1..0..0....1..1..1..0....1..0..0..0....0..0..1..0....1..0..1..0
..1..1..1..1....1..1..1..0....1..1..1..1....1..1..0..0....1..1..0..0
		

Crossrefs

Cf. A266470.

A266468 Number of nX6 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.

Original entry on oeis.org

2, 8, 39, 261, 2090, 18808, 175180, 1595005, 13720886, 109830369, 814603355, 5605474331, 35922351069, 215377645103, 1213816837380, 6458765687442, 32580784869691, 156385330035183, 716642920656832
Offset: 1

Views

Author

R. H. Hardin, Dec 29 2015

Keywords

Comments

Column 6 of A266470.

Examples

			Some solutions for n=4
..0..0..0..0..0..1....0..0..0..1..1..1....0..0..0..0..0..1....0..1..1..1..1..1
..0..0..0..0..1..0....1..1..1..0..0..0....0..0..1..1..1..0....1..0..0..1..1..1
..1..1..1..1..0..0....1..1..1..0..0..0....1..1..0..0..0..0....1..0..1..0..0..0
..1..1..1..1..1..1....1..1..1..0..0..0....1..1..1..1..1..0....1..1..0..0..0..0
		

Crossrefs

Cf. A266470.
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