A190102 Number of 1:3:sqrt(10) proportioned triangles on a (n+1) X (n+1) grid.

0, 0, 24, 80, 168, 344, 624, 1008, 1584, 2368, 3360, 4704, 6384, 8408, 10984, 14064, 17664, 22056, 27152, 32976, 39888, 47736, 56544, 66776, 78216, 90888, 105360, 121344, 138864, 158616, 180216, 203688, 229856, 258248, 288888, 322728, 359200

Offset

1,3

Links

R. H. Hardin, Table of n, a(n) for n = 1..99

Formula

Empirical: a(n) = a(n-1) +2*a(n-3) -2*a(n-4) -a(n-6) +a(n-7) +a(n-9) -a(n-11) -2*a(n-12) +2*a(n-14) +a(n-15) -a(n-17) -a(n-19) +a(n-20) +2*a(n-22) -2*a(n-23) -a(n-25) +a(n-26)

Example

Some solutions for n=5
..5..3....1..2....3..0....4..5....1..1....1..4....3..1....5..3....0..2....2..4
..2..0....1..5....3..3....3..5....1..4....2..5....0..4....2..3....0..1....1..4
..4..4....2..2....4..0....4..2....2..1....4..1....2..0....5..2....3..2....2..1

Crossrefs

Main diagonal of A190103.

Sequence in context: A206003 A143839 A114818 * A060673 A167561 A211575

Adjacent sequences: A190099 A190100 A190101 * A190103 A190104 A190105

Keyword

nonn

Author

R. H. Hardin, May 04 2011

Status

approved