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

A213690 Half the number of (n+1)X(n+1) symmetric 0..1 arrays with no 2X2 subblock summing to 2.

Original entry on oeis.org

3, 13, 70, 529, 5148, 68798, 1220409, 29377751, 949700962, 41536397680, 2450653487731, 195553849371916, 21091722699002539, 3077853629320011499, 607688763160596614184, 162407853243770174812161
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Column 1 of A213697

Examples

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

A213698 Half the number of 3 X 3 0..n symmetric arrays with no 2 X 2 subblock summing to 2n.

Original entry on oeis.org

13, 192, 1320, 5470, 17499, 45892, 105856, 219564, 421825, 758560, 1296408, 2117882, 3336655, 5087460, 7549184, 10927192, 15486741, 21525024, 29417800, 39578070, 52519203, 68796772, 89091840, 114132100, 144799369, 182025792
Offset: 1

Views

Author

R. H. Hardin, Jun 18 2012

Keywords

Comments

Row 2 of A213697.

Examples

			Some solutions for n=4:
..0..3..4....2..0..1....0..1..1....4..4..4....3..0..0....2..4..3....3..1..1
..3..0..3....0..2..0....1..3..2....4..1..2....0..1..4....4..3..2....1..2..0
..4..3..3....1..0..0....1..2..4....4..2..4....0..4..2....3..2..2....1..0..2
		

Crossrefs

Cf. A213697.

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) - 11*a(n-3) + 6*a(n-4) + 14*a(n-5) - 14*a(n-6) - 6*a(n-7) + 11*a(n-8) - a(n-9) - 3*a(n-10) + a(n-11).
Empirical g.f.: x*(13 + 153*x + 731*x^2 + 1461*x^3 + 1803*x^4 + 1111*x^5 + 425*x^6 + 59*x^7 + 4*x^8) / ((1 - x)^7*(1 + x)^4). - Colin Barker, Jul 22 2018

A213699 Half the number of 4X4 0..n symmetric arrays with no 2X2 subblock summing to 2n.

Original entry on oeis.org

70, 7827, 208072, 2322599, 16537086, 84059234, 342943680, 1169405354, 3500184570, 9372540629, 23022951048, 52423261153, 112270651514, 227577256564, 440658095360, 818409534692, 1466948929086, 2544850623111, 4291394833480
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Row 3 of A213697

Examples

			Some solutions for n=4
..0..3..4..0....2..3..1..3....3..0..4..4....2..3..2..2....0..1..2..2
..3..3..2..3....3..4..3..3....0..2..4..3....3..2..0..0....1..4..2..4
..4..2..2..2....1..3..1..0....4..4..0..4....2..0..3..1....2..2..1..0
..0..3..2..3....3..3..0..3....4..3..4..3....2..0..1..0....2..4..0..2
		

Formula

Empirical: a(n) = 3*a(n-1) +5*a(n-2) -23*a(n-3) -4*a(n-4) +76*a(n-5) -28*a(n-6) -140*a(n-7) +98*a(n-8) +154*a(n-9) -154*a(n-10) -98*a(n-11) +140*a(n-12) +28*a(n-13) -76*a(n-14) +4*a(n-15) +23*a(n-16) -5*a(n-17) -3*a(n-18) +a(n-19)

A213700 Half the number of 5X5 0..n symmetric arrays with no 2X2 subblock summing to 2n.

Original entry on oeis.org

529, 750261, 109820000, 4286833981, 83545858925, 976919547736, 8159542628448, 51964311225934, 271341777491743, 1197645088919101, 4637119560078960, 16013821321719463, 50395763900241707, 145985579644461562
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Row 4 of A213697

Examples

			Some solutions for n=4
..0..3..2..3..4....3..0..0..1..4....0..4..0..2..3....0..1..2..2..4
..3..4..3..1..3....0..2..3..1..1....4..2..0..3..3....1..2..4..1..0
..2..3..4..2..4....0..3..2..4..3....0..0..4..3..1....2..4..2..3..1
..3..1..2..4..1....1..1..4..1..4....2..3..3..2..0....2..1..3..1..4
..4..3..4..1..1....4..1..3..4..3....3..3..1..0..4....4..0..1..4..4
		

A213701 Half the number of 6X6 0..n symmetric arrays with no 2X2 subblock summing to 2n.

Original entry on oeis.org

5148, 168382284, 193946752094, 34389632236877, 2256314178023600, 72037480156866493, 1425762604012263360, 19265705246048238885, 196522537519121864954, 1582723194473524459497, 10592676749133340851406
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Row 5 of A213697

Examples

			Some solutions for n=4
..4..4..4..3..4..3....0..3..2..2..1..2....4..2..4..2..2..1....0..3..2..1..3..4
..4..0..1..1..2..3....3..3..4..1..0..4....2..3..1..0..1..0....3..4..4..4..2..1
..4..1..3..4..2..3....2..4..4..1..2..4....4..1..1..0..4..4....2..4..4..1..0..1
..3..1..4..0..1..4....2..1..1..3..3..3....2..0..0..4..3..4....1..4..1..1..0..4
..4..2..2..1..3..3....1..0..2..3..0..4....2..1..4..3..1..1....3..2..0..0..0..3
..3..3..3..4..3..0....2..4..4..3..4..4....1..0..4..4..1..0....4..1..1..4..3..1
		

A213702 Half the number of 7X7 0..n symmetric arrays with no 2X2 subblock summing to 2n.

Original entry on oeis.org

68798, 88681187619, 1146407046198040, 1199143411128185584, 325754552781442854792, 33704464361612549676417, 1829651398830137742302620, 59594337869095766240501287, 1329775905386553460207679334
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Row 6 of A213697

Examples

			Some solutions for n=4
..0..1..2..3..3..4..2....4..2..1..3..0..1..4....4..4..2..1..4..1..0
..1..3..0..1..4..3..3....2..2..4..3..0..0..1....4..1..2..0..4..0..3
..2..0..0..3..4..2..2....1..4..2..4..2..3..0....2..2..1..0..0..0..2
..3..1..3..1..4..1..4....3..3..4..1..3..4..4....1..0..0..3..2..0..3
..3..4..4..4..3..1..0....0..0..2..3..4..4..3....4..4..0..2..3..4..3
..4..3..2..1..1..1..3....1..0..3..4..4..4..3....1..0..0..0..4..1..2
..2..3..2..4..0..3..2....4..1..0..4..3..3..0....0..3..2..3..3..2..0
		

A213691 Half the number of (n+1)X(n+1) symmetric 0..2 arrays with no 2X2 subblock summing to 4.

Original entry on oeis.org

11, 192, 7827, 750261, 168382284, 88681187619, 109492322533385, 317058871268862262, 2152886481426876004067, 34281579489759899253123057, 1280103594445094955653155909620, 112093309434087933528612875492895053
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Column 2 of A213697

Examples

			Some solutions for n=4
..0..0..2..0..0....0..0..2..1..0....2..2..2..1..1....0..2..0..0..1
..0..0..1..2..0....0..1..2..0..2....2..0..2..2..1....2..1..2..0..1
..2..1..1..2..2....2..2..0..0..0....2..2..1..0..2....0..2..2..2..2
..0..2..2..0..1....1..0..0..2..0....1..2..0..2..1....0..0..2..0..1
..0..0..2..1..1....0..2..0..0..0....1..1..2..1..2....1..1..2..1..1
		

A213692 Half the number of (n+1) X (n+1) symmetric 0..3 arrays with no 2 X 2 subblock summing to 6.

Original entry on oeis.org

28, 1320, 208072, 109820000, 193946752094, 1146407046198040, 22678299640600736258, 1501445596428593204920908, 332684482425964910985336666019, 246706401290583205383638262307956104
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Column 3 of A213697.

Examples

			Some solutions for n=4
..0..2..1..0..1....0..0..1..2..0....0..0..3..0..1....2..1..1..2..1
..2..0..2..2..1....0..3..3..1..1....0..1..3..1..2....1..1..0..2..0
..1..2..0..3..1....1..3..0..1..2....3..3..2..1..0....1..0..3..0..0
..0..2..3..1..2....2..1..1..1..1....0..1..1..3..3....2..2..0..2..1
..1..1..1..2..0....0..1..2..1..0....1..2..0..3..2....1..0..0..1..1
		

Crossrefs

Cf. A213697.

A213693 Half the number of (n+1) X (n+1) symmetric 0..4 arrays with no 2 X 2 subblock summing to 8.

Original entry on oeis.org

56, 5470, 2322599, 4286833981, 34389632236877, 1199143411128185584, 181744271406372884215557, 119728593804039164010819562504
Offset: 1

Views

Author

R. H. Hardin, Jun 18 2012

Keywords

Comments

Column 4 of A213697.

Examples

			Some solutions for n=4
..4..4..4..2..1....3..1..2..4..0....1..2..4..4..0....1..0..0..2..4
..4..4..1..0..1....1..1..2..4..3....2..1..3..4..1....0..1..1..4..3
..4..1..1..0..4....2..2..2..1..1....4..3..2..1..0....0..1..2..2..4
..2..0..0..0..3....4..4..1..1..2....4..4..1..0..0....2..4..2..1..4
..1..1..4..3..1....0..3..1..2..0....0..1..0..0..4....4..3..4..4..2
		

Crossrefs

Cf. A213697.

A213694 Half the number of (n+1)X(n+1) symmetric 0..5 arrays with no 2X2 subblock summing to 10.

Original entry on oeis.org

99, 17499, 16537086, 83545858925, 2256314178023600, 325754552781442854792, 251417716503635583550380605
Offset: 1

Views

Author

R. H. Hardin Jun 18 2012

Keywords

Comments

Column 5 of A213697

Examples

			Some solutions for n=4
..1..4..4..1..0....3..3..2..3..3....2..4..3..0..4....2..3..1..0..3
..4..3..1..5..2....3..3..0..4..1....4..4..1..3..5....3..3..2..2..4
..4..1..0..3..3....2..0..3..4..4....3..1..5..2..2....1..2..5..0..0
..1..5..3..2..3....3..4..4..0..5....0..3..2..2..3....0..2..0..2..3
..0..2..3..3..5....3..1..4..5..2....4..5..2..3..3....3..4..0..3..3
		
Showing 1-10 of 13 results. Next