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A140177 Half the number of n X n symmetric binary matrices with adjacent rows differing in at most two positions. 0
1, 4, 25, 171, 1024, 5452, 27319, 133343, 650240, 3183136, 15730003, 78792479, 401274724 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..13.

CROSSREFS

Sequence in context: A081068 A163072 A278689 * A034494 A084210 A093683

Adjacent sequences:  A140174 A140175 A140176 * A140178 A140179 A140180

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 15 2008

STATUS

approved

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Last modified November 18 02:07 EST 2019. Contains 329242 sequences. (Running on oeis4.)