A201872 - OEIS

A201872

Number of zero-sum -7..7 arrays of n elements with first and second differences also in -7..7

1, 7, 57, 431, 3373, 27647, 232969, 1990383, 17103271, 147612131, 1278588895, 11110113949, 96822737023, 846090334081, 7411911618255, 65073276474339, 572430700911207, 5044195360234563, 44516912275192801, 393415480687909671

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OFFSET

1,2

COMMENTS

Column 7 of A201873

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..208

EXAMPLE

Some solutions for n=6

..6...-1....3....0....0....1....7...-3....4....0....5...-1....5....4....6....0

..1...-2....2...-1....1...-2....5...-3....5....1....4...-5....1...-1...-1....5

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

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

.-2....3....0....0...-1...-1...-4....2...-4...-3...-5....1...-4...-1...-2...-1

.-6....4...-4....0....3....5...-5....6...-5....0...-7....7...-2...-6....1...-6

CROSSREFS

Sequence in context: A201438 A202510 A042187 * A218587 A218838 A082310

Adjacent sequences: A201869 A201870 A201871 * A201873 A201874 A201875

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 06 2011

STATUS

approved