A296414
Number of non-isomorphic abstract almost-equidistant graphs on n vertices in R^2. A graph G is abstract almost-equidistant in R^2 if the complement of G does not contain K_3 and G does not contain K_4 nor K_{2,3}.
Original entry on oeis.org
1, 2, 3, 6, 7, 9, 2, 1, 0
Offset: 1
- Martin Balko, Attila Pór, Manfred Scheucher, Konrad Swanepoel, and Pavel Valtr, Almost-equidistant sets, arXiv:1706.06375 [math.MG], 2017.
- Martin Balko, Attila Pór, Manfred Scheucher, Konrad Swanepoel, and Pavel Valtr, Almost-equidistant sets [supplemental data], 2017.
A363682
Number of plane bipolar posets (i.e., plane bipolar orientations with no transitive edge) with n edges.
Original entry on oeis.org
1, 1, 1, 2, 5, 12, 32, 93, 279, 872, 2830, 9433, 32223, 112527, 400370, 1448520, 5320023, 19802827, 74612164, 284238390, 1093757436, 4247742956, 16636921148, 65671960544, 261111950308, 1045172796381, 4209807155949, 17055625810984, 69476952146529, 284467866640048
Offset: 1
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A:=proc(n,i,j) option remember:
if n=0 and i=0 and j=0 then return 1:
elif n<=0 or j<0 or i<0 then return 0:
else
return A(n-1,i,j)+A(n-1,i-1,j)+A(n-1,i,j+1)+A(n-1,i+1,j-1)+A(n-1,i-1,j+1):
fi:
end proc:
seq(A(n-1,0,0),n=1..20);
Showing 1-2 of 2 results.
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