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A183936 Number of strings of n numbers x(i) in -1..1 with sums of x(i) and of x(i)*x(i+1) both zero 1
1, 1, 3, 7, 21, 45, 121, 261, 723, 1723, 5087, 13091, 38641, 101993, 297423, 800187, 2324961, 6378601, 18544345, 51670725, 150172263, 422922591, 1228542913, 3488055573, 10134018375, 28962183951, 84203226523, 241924870591 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 1 of A183944

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

EXAMPLE

All solutions for n=4

..1....0....0...-1...-1....1....0

..0....0....1....0....0....0...-1

.-1....0....0....0....1....0....0

..0....0...-1....1....0...-1....1

CROSSREFS

Sequence in context: A119959 A329114 A018712 * A027151 A219589 A092203

Adjacent sequences:  A183933 A183934 A183935 * A183937 A183938 A183939

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 08 2011

STATUS

approved

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Last modified August 5 13:12 EDT 2021. Contains 346469 sequences. (Running on oeis4.)