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A225992 Number of pairs of orthogonal (-3,4) vectors of length 7*n. 1
420, 8168160, 106322711040, 1496349265582080, 22046445329510891520, 329200486775643608186880, 4991630444756812041482665984, 76438688358604087005593563299840, 1179634366672136518672486151133069312 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A225987.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..64

EXAMPLE

Some solutions for n=1

.-3..4...-3..4...-3..4...-3..4....4..4...-3..4....4..4...-3.-3...-3.-3....4..4

.-3..4....4..4...-3.-3....4..4...-3..4....4.-3...-3..4...-3.-3...-3.-3....4..4

.-3..4....4.-3...-3.-3....4..4....4..4....4..4....4..4...-3..4...-3..4...-3..4

..4..4....4..4...-3..4...-3..4...-3..4....4.-3...-3..4...-3..4...-3..4....4.-3

..4.-3....4.-3...-3.-3....4.-3....4.-3...-3..4....4..4....4.-3...-3.-3...-3..4

..4..4...-3..4...-3.-3....4..4....4..4....4..4....4.-3...-3.-3...-3.-3....4..4

..4..4....4..4...-3..4...-3..4....4.-3....4..4...-3..4...-3.-3...-3..4....4.-3

CROSSREFS

Sequence in context: A223941 A046167 A059951 * A028683 A198163 A014890

Adjacent sequences:  A225989 A225990 A225991 * A225993 A225994 A225995

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 22 2013

STATUS

approved

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Last modified May 26 13:59 EDT 2022. Contains 354092 sequences. (Running on oeis4.)