A245999 Number of length 4+2 0..n arrays with no pair in any consecutive three terms totalling exactly n.

2, 26, 396, 2196, 9582, 29790, 80504, 185192, 391290, 753570, 1371972, 2352636, 3877286, 6128486, 9405552, 13997520, 20363634, 28934442, 40377980, 55306340, 74651742, 99252846, 130367976, 169112376, 217138922, 275894450, 347501364

Offset

1,1

Comments

Row 4 of A245995.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) -11*a(n-3) +6*a(n-4) +14*a(n-5) -14*a(n-6) -6*a(n-7) +11*a(n-8) -a(n-9) -3*a(n-10) +a(n-11).

Empirical: G.f.: -2*x*(1 +10*x +158*x^2 +502*x^3 +1436*x^4 +1510*x^5 +1498*x^6 +474*x^7 +171*x^8) / ( (1+x)^4*(x-1)^7 ). - R. J. Mathar, Aug 10 2014

Example

Some solutions for n=8
..1....2....1....3....2....0....0....1....1....0....4....0....2....5....5....3
..4....7....3....2....0....2....2....5....1....7....1....2....2....2....2....7
..5....5....4....1....7....1....5....5....5....6....6....3....7....1....5....7
..6....5....1....4....2....8....4....7....8....5....3....4....7....8....7....5
..8....0....5....0....2....1....8....7....4....4....6....1....4....5....0....2
..4....1....6....1....7....8....7....4....6....7....1....1....7....5....6....2

Crossrefs

Cf. A245995.

Sequence in context: A057351 A350436 A359924 * A355725 A285026 A137100

Adjacent sequences: A245996 A245997 A245998 * A246000 A246001 A246002

Keyword

nonn

Author

R. H. Hardin, Aug 09 2014

Status

approved