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A145761 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either three adjacent vertically or three adjacent horizontally. 0
1, 1, 1, 1, 2, 3, 6, 9, 29, 71, 252, 692, 3368, 13077, 79134, 377418, 2968590, 18765157, 189063004, 1516592933, 19680440925, 204860397699, 3422227126547, 45691959144342, 982062906171101, 16911337817136038, 468085274414196900 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
CROSSREFS
Sequence in context: A349148 A002076 A286435 * A071714 A077753 A353122
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 17 2008
STATUS
approved

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Last modified July 20 20:50 EDT 2024. Contains 374459 sequences. (Running on oeis4.)