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A225991 Number of pairs of orthogonal (-1,4) vectors of length 5*n. 1
45, 26010, 21594300, 15593341800, 11432293516320, 8690522384325600, 6699690552347865600, 5206881575348541978240, 4077143683681515029088000, 3212142498665023117259125760, 2542945288539007875744064972800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A225987.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..107

EXAMPLE

Some solutions for n=1

.-1..4...-1..4....4..4...-1..4...-1..4...-1.-1...-1..4....4..4...-1..4...-1..4

..4..4...-1..4...-1..4....4.-1....4..4...-1.-1....4.-1...-1..4....4.-1....4..4

..4.-1...-1..4...-1..4....4.-1...-1..4...-1.-1....4..4...-1..4....4..4...-1..4

..4.-1....4..4...-1..4...-1..4...-1..4...-1..4...-1..4....4.-1....4.-1...-1..4

.-1..4...-1..4...-1..4....4..4...-1..4...-1.-1....4.-1....4.-1...-1..4....4.-1

CROSSREFS

Sequence in context: A199521 A007537 A287434 * A125113 A003739 A300198

Adjacent sequences:  A225988 A225989 A225990 * A225992 A225993 A225994

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 22 2013

STATUS

approved

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Last modified January 24 22:45 EST 2022. Contains 350565 sequences. (Running on oeis4.)