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.

A239030 T(n,k)=Number of nXk 0..2 arrays with no element equal to the sum of elements to its left or one plus the sum of the elements above it, modulo 3.

Original entry on oeis.org

1, 1, 2, 1, 3, 2, 1, 4, 4, 4, 1, 5, 7, 11, 4, 1, 6, 11, 28, 16, 8, 1, 7, 16, 59, 54, 43, 8, 1, 8, 22, 110, 149, 212, 64, 16, 1, 9, 29, 189, 354, 806, 428, 171, 16, 1, 10, 37, 306, 757, 2592, 2195, 1652, 256, 32, 1, 11, 46, 473, 1495, 7265, 9319, 11768, 3410, 683, 32, 1, 12, 56
Offset: 1

Views

Author

R. H. Hardin, Mar 09 2014

Keywords

Comments

Table starts
..1...1.....1......1.......1........1.........1.........1..........1
..2...3.....4......5.......6........7.........8.........9.........10
..2...4.....7.....11......16.......22........29........37.........46
..4..11....28.....59.....110......189.......306.......473........704
..4..16....54....149.....354......757......1495......2773.......4888
..8..43...212....806....2592.....7265.....18362.....42809......93464
..8..64...428...2195....9319....33699....107611....311585.....833304
.16.171..1652..11768...69288...339315...1435014...5388959...18371174
.16.256..3410..33417..265247..1719471...9453266..45358859..194626082
.32.683.13004.177087.1965398.17562449.131139508.838702960.4711005062

Examples

			Some solutions for n=5 k=4
..2..0..0..0....2..0..0..0....2..0..0..0....2..0..0..0....2..0..0..0
..2..0..0..0....1..2..2..0....2..0..0..0....1..0..2..2....1..2..2..0
..1..0..2..2....2..1..2..0....1..0..2..2....2..0..1..2....2..1..2..0
..2..0..1..1....2..0..1..2....1..0..2..1....2..0..0..1....2..0..1..2
..1..0..2..2....1..0..2..2....2..0..0..0....1..0..2..1....1..2..2..1
		

Crossrefs

Column 1 is A016116
Row 2 is A000027(n+1)
Row 3 is A000124

Formula

Empirical for column k:
k=1: a(n) = 2*a(n-2)
k=2: a(n) = 5*a(n-2) -4*a(n-4)
k=3: a(n) = 17*a(n-2) -96*a(n-4) +210*a(n-6) -152*a(n-8)
k=4: [order 18]
k=5: [order 38]
k=6: [order 90]
Empirical for row n:
n=1: a(n) = 1
n=2: a(n) = n + 1
n=3: a(n) = (1/2)*n^2 + (1/2)*n + 1
n=4: a(n) = (1/12)*n^4 - (1/6)*n^3 + (47/12)*n^2 - (29/6)*n + 5
n=5: [polynomial of degree 6] for n>1
n=6: [polynomial of degree 9] for n>2
n=7: [polynomial of degree 12] for n>3