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.

A207453 T(n,k) = Number of n X k 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 1 vertically.

Original entry on oeis.org

2, 4, 4, 6, 16, 6, 10, 36, 36, 8, 16, 100, 90, 64, 10, 26, 256, 330, 168, 100, 12, 42, 676, 1008, 760, 270, 144, 14, 68, 1764, 3354, 2560, 1450, 396, 196, 16, 110, 4624, 10710, 10088, 5200, 2460, 546, 256, 18, 178, 12100, 34884, 36456, 23530, 9216, 3850, 720
Offset: 1

Views

Author

R. H. Hardin, Feb 17 2012

Keywords

Comments

Table starts
..2...4...6...10....16.....26.....42......68......110......178.......288
..4..16..36..100...256....676...1764....4624....12100....31684.....82944
..6..36..90..330..1008...3354..10710...34884...112530...364722...1179360
..8..64.168..760..2560..10088..36456..138176...509960..1910296...7096320
.10.100.270.1450..5200..23530..92610..396100..1610950..6754210..27799200
.12.144.396.2460..9216..46956.196812..932688..4086060.18819228..83939328
.14.196.546.3850.14896..84266.370734.1922564..8935850.44655394.212625504
.16.256.720.5680.22528.139984.640080.3599104.17556880.94358512.474439680

Examples

			Some solutions for n=5, k=3
..1..0..1....1..1..0....1..1..1....0..1..1....0..1..0....0..1..0....0..1..1
..1..0..1....1..0..0....0..1..1....0..1..1....0..1..1....1..0..0....1..0..1
..1..0..1....1..0..0....0..1..0....0..1..0....0..1..1....1..0..0....1..0..1
..1..0..1....1..0..0....0..1..0....0..1..0....0..1..0....1..0..0....1..0..1
..1..0..0....1..0..0....0..1..0....0..1..0....0..1..0....1..0..0....1..0..1
		

Crossrefs

Column 2 is A016742.
Column 3 is A152746.
Row 1 is A006355(n+2).
Row 2 is A206981.

Formula

Empirical for column k:
k=1: a(n) = 2*n;
k=2: a(n) = 4*n^2;
k=3: a(n) = 12*n^2 - 6*n;
k=4: a(n) = 10*n^3 + 10*n^2 - 10*n;
k=5: a(n) = 48*n^3 - 32*n^2;
k=6: a(n) = 26*n^4 + 78*n^3 - 104*n^2 + 26*n;
k=7: a(n) = 168*n^4 - 84*n^3 - 84*n^2 + 42*n;
k=8: a(n) = 68*n^5 + 408*n^4 - 612*n^3 + 204*n^2;
k=9: a(n) = 550*n^5 - 990*n^3 + 660*n^2 - 110*n;
k=10: a(n) = 178*n^6 + 1780*n^5 - 2670*n^4 + 534*n^3 + 534*n^2 - 178*n;
k=11: a(n) = 1728*n^6 + 1440*n^5 - 6912*n^4 + 5184*n^3 - 1152*n^2;
k=12: a(n) = 466*n^7 + 6990*n^6 - 9320*n^5 - 2796*n^4 + 8388*n^3 - 3728*n^2 + 466*n;
k=13: a(n) = 5278*n^7 + 10556*n^6 - 36946*n^5 + 27144*n^4 - 3016*n^3 - 3016*n^2 + 754*n;
k=14: a(n) = 1220*n^8 + 25620*n^7 - 25620*n^6 - 42700*n^5 + 73200*n^4 - 36600*n^3 + 6100*n^2;
k=15: a(n) = 15792*n^8 + 55272*n^7 - 165816*n^6 + 98700*n^5 + 39480*n^4 - 59220*n^3 + 19740*n^2 - 1974*n.
Empirical for row n:
n=1: a(k)=a(k-1)+a(k-2);
n=2: a(k)=2*a(k-1)+2*a(k-2)-a(k-3);
n=3: a(k)=a(k-1)+7*a(k-2)+2*a(k-3)-4*a(k-4);
n=4: a(k)=a(k-1)+10*a(k-2)+3*a(k-3)-9*a(k-4);
n=5: a(k)=a(k-1)+13*a(k-2)+4*a(k-3)-16*a(k-4);
n=6: a(k)=a(k-1)+16*a(k-2)+5*a(k-3)-25*a(k-4);
n=7: a(k)=a(k-1)+19*a(k-2)+6*a(k-3)-36*a(k-4);
apparently for row n>2: a(k)=a(k-1)+(3*n-2)*a(k-2)+(n-1)*a(k-3)+(n-1)^2*a(k-4).