A212785 Half the number of 0..n arrays of length 6 with second differences nonzero

13, 162, 1238, 5104, 16594, 43727, 101743, 211461, 408430, 735896, 1261599, 2064329, 3259612, 4975687, 7395946, 10715635, 15205983, 21151890, 28937100, 38956477, 51737361, 67810309, 87873466, 112625630, 142969752, 179799242

Offset

1,1

Comments

Row 4 of A212782

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = a(n-2) +2*a(n-3) +2*a(n-4) -a(n-5) -2*a(n-6) -5*a(n-7) -3*a(n-8) +3*a(n-10) +6*a(n-11) +5*a(n-12) +3*a(n-13) -3*a(n-14) -5*a(n-15) -6*a(n-16) -3*a(n-17) +3*a(n-19) +5*a(n-20) +2*a(n-21) +a(n-22) -2*a(n-23) -2*a(n-24) -a(n-25) +a(n-27)

Example

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

Crossrefs

Sequence in context: A118673 A216300 A250417 * A133180 A090134 A087400

Adjacent sequences: A212782 A212783 A212784 * A212786 A212787 A212788

Keyword

nonn

Author

R. H. Hardin May 27 2012

Status

approved