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A202967 Number of arrays of 7 integers in -n..n with sum zero and adjacent elements differing in absolute value 1
6, 524, 9872, 66208, 289536, 941086, 2537024, 5933492, 12515772, 24295760, 44188086, 76110890, 125357152, 198686606, 304811136, 454458544, 660981870, 940393644, 1312104510, 1798910920, 2427885688, 3230300850, 4242680088 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A202962

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-2) +a(n-3) -2*a(n-5) +a(n-6) -3*a(n-7) +3*a(n-8) -a(n-9) +2*a(n-10) +a(n-11) -a(n-13) -2*a(n-14) +a(n-15) -3*a(n-16) +3*a(n-17) -a(n-18) +2*a(n-19) -a(n-21) +a(n-22) -2*a(n-23) +a(n-24)

EXAMPLE

Some solutions for n=4

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A222607 A000411 A180431 * A230330 A252174 A251697

Adjacent sequences:  A202964 A202965 A202966 * A202968 A202969 A202970

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 26 2011

STATUS

approved

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Last modified June 1 18:43 EDT 2020. Contains 334762 sequences. (Running on oeis4.)