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 1-7 of 7 results.

A221825 Number of nX3 arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 16, 202, 2930, 41618, 592601, 8434490, 120053263, 1708776751, 24321871624, 346185271087, 4927426856495, 70134512879660, 998259343308353, 14208720864088015, 202239778618252032, 2878579180120974241
Offset: 1

Views

Author

R. H. Hardin Jan 26 2013

Keywords

Comments

Column 3 of A221828

Examples

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

Formula

Empirical: a(n) = 17*a(n-1) -39*a(n-2) -14*a(n-3) +134*a(n-4) -161*a(n-5) +50*a(n-6) -147*a(n-7) +129*a(n-8) +215*a(n-9) -131*a(n-10) +53*a(n-11) -92*a(n-12) -97*a(n-13) +31*a(n-14) -27*a(n-15) +16*a(n-16) +6*a(n-17)

A221826 Number of nX4 arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 73, 2879, 115417, 4755445, 194407111, 7954432829, 325446165881, 13315083231576, 544765825231628, 22288229643043523, 911887582567144091, 37308434607556030347, 1526415443763878545790, 62450867501566841285468
Offset: 1

Views

Author

R. H. Hardin Jan 26 2013

Keywords

Comments

Column 4 of A221828

Examples

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

A221829 Number of 2 X n arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 3, 16, 73, 333, 1519, 6929, 31607, 144177, 657671, 3000001, 13684663, 62423313, 284747239, 1298889569, 5924953367, 27026987697, 123285031751, 562371183361, 2565285853303, 11701686899793, 53377862792359, 243485940162209
Offset: 1

Views

Author

R. H. Hardin, Jan 26 2013

Keywords

Comments

Row 2 of A221828.

Examples

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

Crossrefs

Cf. A221828.

Formula

Empirical: a(n) = 5*a(n-1) - 2*a(n-2) for n>4.
Conjectures from Colin Barker, Aug 11 2018: (Start)
G.f.: x^2*(3 + x - x^2) / (1 - 5*x + 2*x^2).
a(n) = (2^(-4-n)*((5-sqrt(17))^n*(-7+sqrt(17)) + (5+sqrt(17))^n*(7+sqrt(17)))) / sqrt(17) for n>2.
(End)

A221830 Number of 3Xn arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 14, 202, 2879, 40983, 583419, 8304016, 118195328, 1682332699, 23945477164, 340827864824, 4851172222091, 69049142818994, 982810732310121, 13988833113623959, 199110007092542464, 2834031588079597413
Offset: 1

Views

Author

R. H. Hardin Jan 26 2013

Keywords

Comments

Row 3 of A221828

Examples

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

Formula

Empirical: a(n) = 17*a(n-1) -39*a(n-2) -14*a(n-3) +134*a(n-4) -161*a(n-5) +50*a(n-6) -147*a(n-7) +129*a(n-8) +215*a(n-9) -131*a(n-10) +53*a(n-11) -92*a(n-12) -97*a(n-13) +31*a(n-14) -27*a(n-15) +16*a(n-16) +6*a(n-17) for n>18

A221831 Number of 4Xn arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 64, 2930, 115417, 4715043, 192788993, 7888216533, 322723834959, 13203608881221, 540203150208573, 22101534579211095, 904249026745794715, 36995912673327194833, 1513629078095632460534, 61927733346071816062294
Offset: 1

Views

Author

R. H. Hardin Jan 26 2013

Keywords

Comments

Row 4 of A221828

Examples

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

A221827 Number of nX5 arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 333, 40983, 4715043, 570066685, 68489860450, 8224749361083, 987885812260577, 118641972922938733, 14248324215718943851, 1711142647446159966808
Offset: 1

Views

Author

R. H. Hardin Jan 26 2013

Keywords

Comments

Column 5 of A221828

Examples

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

A221832 Number of 5 X n arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, without 2-loops or left turns.

Original entry on oeis.org

0, 292, 41618, 4755445, 570066685, 68573607669, 8233561918895, 988927665068644, 118765199887208210
Offset: 1

Views

Author

R. H. Hardin, Jan 26 2013

Keywords

Comments

Row 5 of A221828.

Examples

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

Crossrefs

Cf. A221828.
Showing 1-7 of 7 results.