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A226000 Number of pairs of orthogonal (-2,7) vectors of length 9*n. 1
2376, 473173920, 142896990300480, 20278050662801226240, 3273835406669841316064256, 637732143080315479532514447360, 115448330868966954716300528059883520 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 14 of A225987.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..46

EXAMPLE

Some solutions for n=1

.-2..7...-2..7...-2..7...-2..7...-2..7...-2..7....7..7...-2..7...-2..7....7..7

..7.-2....7.-2....7.-2....7..7....7..7....7..7...-2..7....7.-2...-2..7...-2..7

.-2..7...-2..7....7..7...-2..7...-2..7...-2..7....7.-2....7..7....7..7...-2..7

..7..7....7..7...-2..7...-2..7....7.-2....7.-2....7..7...-2..7...-2..7....7.-2

.-2..7....7.-2...-2..7...-2..7....7.-2....7..7...-2..7....7.-2....7.-2...-2..7

..7..7...-2..7....7..7...-2..7...-2..7....7.-2...-2..7....7..7...-2..7....7..7

..7.-2....7.-2...-2..7...-2..7....7.-2....7.-2....7.-2....7.-2...-2..7...-2..7

.-2..7....7..7....7.-2....7..7....7..7...-2..7...-2..7....7.-2...-2..7...-2..7

.-2..7...-2..7....7.-2...-2..7...-2..7...-2..7....7.-2....7.-2....7..7...-2..7

CROSSREFS

Sequence in context: A250588 A165948 A183599 * A163026 A069300 A255800

Adjacent sequences:  A225997 A225998 A225999 * A226001 A226002 A226003

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 22 2013

STATUS

approved

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Last modified February 28 09:24 EST 2021. Contains 341695 sequences. (Running on oeis4.)