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 A265197 #20 Jan 15 2025 16:42:21 %S A265197 711,1251,1527,1712,2132,2486,2616,2812,2934,3357,3441,3781,3812,4156, %T A265197 4288,4842,4971,4972,5034,5346,5382,5659,5842,5886,6147,6159,6402, %U A265197 6734,6747,7062,7312,7403,7592,7722,8034,8102,8342,8831,8862,8961,9092,9117 %N A265197 Magic sums of 3 X 3 semimagic squares composed of triangular numbers. %C A265197 These semimagic squares are composed of 9 distinct triangular numbers >= 0. %H A265197 Wikipedia, <a href="https://en.wikipedia.org/wiki/Triangular_number">Triangular number</a> %H A265197 <a href="/index/Mag#magic">Index entries for sequences related to magic squares</a> %e A265197 A semimagic square with sum 1527: %e A265197 |----|----|----| %e A265197 | 0 |351 |1176| %e A265197 |----|----|----| %e A265197 |666 |741 |120 | %e A265197 |----|----|----| %e A265197 |861 |435 |231 | %e A265197 |----|----|----| %Y A265197 Cf. A000217, A265141, A265198, A269060 (for positive triangular numbers). %K A265197 nonn %O A265197 1,1 %A A265197 _Arkadiusz Wesolowski_, Dec 04 2015