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.

A241306 T(n,k)=Number of nXk 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.

Original entry on oeis.org

2, 2, 5, 4, 6, 11, 6, 15, 6, 25, 8, 25, 37, 12, 57, 14, 40, 74, 116, 16, 129, 20, 89, 186, 330, 304, 28, 293, 30, 121, 646, 1462, 1145, 869, 38, 665, 48, 237, 1278, 5757, 6718, 4499, 2398, 66, 1509, 70, 390, 3418, 22343, 49918, 41336, 15827, 6813, 92, 3425, 108, 682
Offset: 1

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Author

R. H. Hardin, Apr 18 2014

Keywords

Comments

Table starts
....2...2.....4......6........8.........14..........20..........30..........48
....5...6....15.....25.......40.........89.........121.........237.........390
...11...6....37.....74......186........646........1278........3418........9113
...25..12...116....330.....1462.......5757.......22343.......79043......304799
...57..16...304...1145.....6718......49918......283985.....1666242.....9581018
..129..28...869...4499....41336.....490486.....5098814....41458261...447396605
..293..38..2398..15827...217785....3893262....70316883...978925384.16677156613
..665..66..6813..58043..1215485...37039909..1194164944.30759996872
.1509..92.18782.209838..6526016..307030328.16586413847
.3425.154.53067.757771.35833494.2801405991

Examples

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

Crossrefs

Column 1 is A239812
Row 1 is A239851

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +2*a(n-2) +2*a(n-3)
k=2: a(n) = 2*a(n-2) +a(n-3) -a(n-5)
Empirical for row n:
n=1: a(n) = a(n-2) +2*a(n-3)
n=2: [order 14] for n>20