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Place n equally space points around the circumference of a circle and then, for each pair of points, draw two distinct circles, whose radii are the same as the first circle, such that both points lie on their circumferences. The sequence gives the total number of (curved) edges formed.
9

%I #11 Mar 22 2024 09:14:33

%S 1,2,12,12,75,66,350,360,1071,1150,2684,2148,5603,5950,10110,10928,

%T 18309,16830,29564,30500,44961,46882,66746,64872,95125,97786,131112,

%U 135156,177567,169770,235042,240928,304359,312086,389340,388764,491175,503158,610662,624280,752145,749742,917276

%N Place n equally space points around the circumference of a circle and then, for each pair of points, draw two distinct circles, whose radii are the same as the first circle, such that both points lie on their circumferences. The sequence gives the total number of (curved) edges formed.

%C See A371373 and A371374 for images of the graphs.

%F a(n) = A371373(n) + A371374(n) - 1 by Euler's formula.

%Y Cf. A371373 (vertices), A371374 (regions), A371376 (k-gons), A371377 (vertex crossings), A371255, A135565, A358783, A359047.

%K nonn

%O 1,2

%A _Scott R. Shannon_, Mar 20 2024