A200437 Number of -n..n arrays x(0..9) of 10 elements with zero sum and no two or three adjacent elements summing to zero

0, 23674, 1432402, 24220966, 210222830, 1206988576, 5230842688, 18491305412, 56022717236, 150412523630, 366439267062, 824236891962, 1734285496242, 3448292160196, 6530868950100, 11857838629608, 20748002017096

Offset

1,2

Comments

Row 7 of A200430

Links

R. H. Hardin, Table of n, a(n) for n = 1..34

Formula

Empirical: a(n) = (124952/567)*n^9 - (282778/315)*n^8 + (4520071/1890)*n^7 - (849277/180)*n^6 + (731309/108)*n^5 - (629357/90)*n^4 + (55560059/11340)*n^3 - (870757/420)*n^2 + (50299/126)*n

Example

Some solutions for n=3
.-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3...-3
.-2...-2...-3...-3...-2...-2...-3...-2...-1...-3...-1...-1...-3...-2...-3...-2
.-2....0....1....0....1...-3....2....0....0....1....2....0....1...-2....0...-2
.-2...-2...-2....2....0....1....0....3...-1....1....1...-3....0....0....1....0
..1...-3...-1....2....3...-2....1....0...-1....1....3....0....1....3...-3...-1
..2....1....0....2....0....3....1...-2....0....1...-2...-1....3....1...-2...-3
..1....3....2...-3...-2....3....3....1....3...-3....3....2...-2....2....3....2
..3....3....3....2....1...-1...-2....2....1....1....1....1....0....2....3....3
..0....1....3....2....0....3....0...-1....2....3...-2....2....1....2....3....3
..2....2....0...-1....2....1....1....2....0....1...-2....3....2...-3....1....3

Crossrefs

Sequence in context: A069334 A118061 A251855 * A223342 A179918 A168169

Adjacent sequences: A200434 A200435 A200436 * A200438 A200439 A200440

Keyword

nonn

Author

R. H. Hardin Nov 17 2011

Status

approved