A183939 - OEIS

A183939

Number of strings of n numbers x(i) in -4..4 with sums of x(i) and of x(i)*x(i+1) both zero

1, 1, 9, 33, 321, 1411, 10613, 70449, 534153, 3908739, 31172293, 247959153, 2040991681, 16818777105, 139873091535, 1164007471357, 9753589044027, 82147216112609, 696523301660651, 5930891437147689, 50682977439086169

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

Column 4 of A183944

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..28

EXAMPLE

Some solutions for n=6

..0....3...-2....4....0...-1....1...-4....4....4...-2....0...-1....4....2....3

.-3...-2....0....0...-3....0....2....1....0....1...-1....4....2...-1...-1....2

..0...-2....3....0...-3....0...-1...-4....1....2....2....0....1....2....2...-1

..2...-2....2...-3....3...-2....0....1...-4...-3....1....0....0....0....1...-1

..3...-1...-3...-4....0....0...-2....4...-1....0...-1....0....0...-3...-1....1

.-2....4....0....3....3....3....0....2....0...-4....1...-4...-2...-2...-3...-4

CROSSREFS

Sequence in context: A186762 A343843 A063423 * A145952 A172498 A276284

Adjacent sequences: A183936 A183937 A183938 * A183940 A183941 A183942

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 08 2011

STATUS

approved