This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A382455 #6 Mar 26 2025 13:26:16 %S A382455 3,9,23,45,75,109,178,220,324,403,545,623,872,945,1238,1397,1725,1878, %T A382455 2390,2530,3087,3317,3968,4212,5057,5256,6186,6569,7569,7893,9201, %U A382455 9511,10890,11359,12863,13340,15135,15543,17492,18145,20170,20739,23212,23784,26325,27100,29813,30598,33727 %N A382455 Order 3 perimeter magic squares of magic sum n, all elements distinct and 1 in the set; bracelet symmetry. %C A382455 The order-3 perimeter-magic square has 3 positive integers (=order) per side (4 at corners, 4 within edges, total 8) where the sum of the 3 integers on each side is the same. Here we require that all 8 integers are distinct, that 1 is one of them, and that rotations and flips are not counted separately (recognizing the bracelet symmetry). %H A382455 R. J. Mathar, <a href="https://zenodo.org/records/15001365">Generating perimeter-magic polygons</a>, C++ (2025). %F A382455 a(n) = A380962(n)-A380962(n-3). %Y A382455 Cf. A380962 (1 not necessarily included), A084569 (elements not necess. distinct). %K A382455 nonn %O A382455 12,1 %A A382455 _R. J. Mathar_, Mar 26 2025