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A211348
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Number of ways to tile an n X n square with 1 X 1, 2 X 2 and 3 X 3 tiles.
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3
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1, 1, 2, 6, 39, 467, 10290, 431842, 33702357, 4933399675, 1353257600290, 694985665826606, 668743276018647665, 1205268925168096642391, 4069023157203412697840109, 25732126785058509461002703360, 304814553338563601845965453449729
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OFFSET
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0,3
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LINKS
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MAPLE
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b:= proc(n, l) option remember; local i, k, s, t;
if max(l[])>n then 0 elif n=0 then 1
elif min(l[])>0 then t:=min(l[]); b(n-t, map(h->h-t, l))
else for k do if l[k]=0 then break fi od; s:=0;
for i from k to min(k+2, nops(l)) while l[i]=0 do s:=s+
b(n, [l[j]$j=1..k-1, 1+i-k$j=k..i, l[j]$j=i+1..nops(l)])
od; s
fi
end:
a:= n-> b(n, [0$n]):
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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