STATUS
editing
approved
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Revision History for A220561
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Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly one horizontal or antidiagonal neighbor
(history; published version)
(history; published version)
LINKS
R. H. Hardin, <a href="/A220561/b220561.txt">Table of n, a(n) for n = 1..210</a>
NAME
allocated for R. H. Hardin
Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly one horizontal or antidiagonal neighbor
DATA
21, 1544, 101052, 6743873, 449429440, 29955561052, 1996515036228, 133064181801048, 8868465829053416, 591065515195237024, 39393331961841054032, 2625486595153945514656, 174983417444316851450400
OFFSET
1,1
COMMENTS
Column 7 of A220562
FORMULA
Empirical: a(n) = 85*a(n-1) -1330*a(n-2) +7350*a(n-3) -15316*a(n-4) +12720*a(n-5) -3168*a(n-6) for n>9
EXAMPLE
Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10)
..0..0..0..0..0..7..0....0..0..0..0..7..6..4....0..0..0..0..0..6..4
..0..6..4..0..3..6..4....6..4..7..3..0..0..0....6..4..6..4..6..4..0
..6..4..6..4..0..0..0....0..3..0..6..4..0..0....6..4..0..0..6..4..0
KEYWORD
allocated
nonn
AUTHOR
R. H. Hardin Dec 16 2012
STATUS
approved
editing
NAME
allocated for R. H. Hardin
KEYWORD
allocated
STATUS
approved