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a(n) is the number of points in the interior of the n-th figure shown in A255011 (meaning the figure with 4n points on the perimeter).
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%I #16 May 27 2020 20:32:04

%S 1,29,245,801,2737,4801,12265,19209,33513,49537,87641,101933,178413,

%T 220057,286297,379033,551601,606169,880217,951365,1208965,1507433,

%U 1947785,2002573,2624309,3055989,3550317,3954937,5068921,5062033,6669541,7081841,8143061,9364953,10296329,10918073,13772225,14842297,16312317

%N a(n) is the number of points in the interior of the n-th figure shown in A255011 (meaning the figure with 4n points on the perimeter).

%C a(n) = A331449(n) - 4*n. Computed from _Lars Blomberg_'s b-file for A331449.

%H N. J. A. Sloane, <a href="/A334690/b334690.txt">Table of n, a(n) for n = 1..52</a>

%Y Cf. A255011, A331448, A331449.

%Y These are the sums of the rows in A334691.

%K nonn

%O 1,2

%A _Scott R. Shannon_ and _N. J. A. Sloane_, May 17 2020