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 A336189 #15 Dec 21 2024 18:37:31 %S A336189 1,48841,151757761,7148452448281,22211509021338121, %T A336189 1046258952151234702321,3250912043200499426917081, %U A336189 153132136343696050161247674961,475808694603918281112156880430641 %N A336189 The perfect square integer sum of a square block of integers, with 1 at the top-left corner, on a diagonally numbered 2D board. %C A336189 See A336186 for the corresponding square edge length and an explanation of the sequence. Note that the currently known terms all end in 1. %H A336189 Eric Angelini, <a href="https://cinquantesignes.blogspot.com/2020/06/prime-squares.html">Prime squares and square squares</a>, personal blog "Cinquante signes", Jun. 29, 2020. %H A336189 Eric Angelini, <a href="/A336186/a336186.pdf">Prime squares and square squares</a>, personal blog "Cinquante signes", Jun. 29, 2020. [Cached copy] %e A336189 a(1) = 1 = 1^2. %e A336189 a(2) = 48841 = 221^2. %e A336189 a(3) = 151757761 = 12319^2. %e A336189 a(4) = 7148452448281 = 2673659^2. %e A336189 a(5) = 22211509021338121 = 149035261^2. %e A336189 a(6) = 1046258952151234702321 = 32345926361^2. %e A336189 a(7) = 3250912043200499426917081 = 1803028575259^2. %e A336189 a(8) = 153132136343696050161247674961 = 391321014441719^2. %e A336189 a(9) = 475808694603918281112156880430641 = 21813039554448121^2. %e A336189 See A336186 for a diagram of the 2D board and examples. %Y A336189 Cf. A336186, A185505, A000290, A000124, A000217. %K A336189 nonn,more %O A336189 1,2 %A A336189 _Scott R. Shannon_ and _Eric Angelini_, Jul 11 2020