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Search: id:A058481
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A058481 a(n)=3^n-2. +0
7
1, 7, 25, 79, 241, 727, 2185, 6559, 19681, 59047, 177145, 531439, 1594321, 4782967, 14348905, 43046719, 129140161, 387420487, 1162261465, 3486784399, 10460353201, 31381059607, 94143178825, 282429536479, 847288609441 (list; graph; listen)
OFFSET

1,2

COMMENT

2 X n binary matrices with no zero rows or columns.

FORMULA

Number of m X n binary matrices with no zero rows or columns is Sum_{j=0..m}(-1)^j*C(m, j)*(2^(m-j)-1)^n.

CROSSREFS

Cf. A055602, A024206 (unlabeled case), A055609, A058482, A000244.

Adjacent sequences: A058478 A058479 A058480 this_sequence A058482 A058483 A058484

Sequence in context: A000970 A048477 A117152 this_sequence A138729 A035509 A141627

KEYWORD

easy,nonn,nice

AUTHOR

Vladeta Jovovic (vladeta(AT)Eunet.yu), Nov 26 2000

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Dec 04 2000

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Last modified October 13 20:18 EDT 2008. Contains 145016 sequences.


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