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A060870 Number of n X n matrices over GF(5) with rank 1. 2
4, 144, 3844, 97344, 2439844, 61027344, 1525839844, 38146777344, 953673339844, 23841853027344, 596046423339844, 14901161071777344, 372529029235839844, 9313225743103027344, 232830643638610839844, 5820766091270446777344 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,200

FORMULA

a(n) = 1/4 * (5^n - 1)^2

EXAMPLE

a(2) = 144 because there are 145 (the second element in sequence A060720) singular 2X2 matrices over GF(5), that have rank <= 1 of which only the zero matrix has rank zero so a(2) = 145 - 1 = 144.

PROG

(PARI) { for (n=1, 200, write("b060870.txt", n, " ", (5^n - 1)^2 / 4); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 13 2009]

CROSSREFS

A060720.

Sequence in context: A134631 A036511 A186720 * A084703 A186418 A122747

Adjacent sequences:  A060867 A060868 A060869 * A060871 A060872 A060873

KEYWORD

nonn,easy

AUTHOR

Ahmed Fares (ahmedfares(AT)my-deja.com), May 04 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001

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Last modified February 17 16:13 EST 2012. Contains 206050 sequences.