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 A140755 #20 Jun 09 2025 00:51:28
%S A140755 43,47,53,61,71,83,97,113,131,151,173,197,223,251,281,313,347,383,421,
%T A140755 461,167,172,179,188,199,212,227,244,263,284,307,332,359,388,419,452,
%U A140755 487,524,563,604,373,379,387,397,409,423,439
%N A140755 Square array read by rows: T(n,k) = 41*n^2 + k^2 + n*k, with 20 columns.
%C A140755 The original definition of this sequence was obscure: "A prime array is embedded in a binary quadratic equation that is a transform of x^2 - x + 41".
%H A140755 G. C. Greubel, <a href="/A140755/b140755.txt">Table of n, a(n) for n = 1..400</a>
%t A140755 With[{m=20}, Table[41*n^2 +k^2 +n*k, {n,m}, {k,m}]//Flatten] (* _G. C. Greubel_, Oct 21 2023 *)
%o A140755 (Magma) m:=20; [41*n^2 +k^2 +n*k: k in [1..m], n in [1..m]]; // _G. C. Greubel_, Oct 21 2023
%o A140755 (SageMath) flatten([[41*n^2+k^2+n*k for k in range(1,21)] for n in range(1,21)]) # _G. C. Greubel_, Oct 21 2023
%Y A140755 Cf. A140340, A140754 (very similar arrays).
%K A140755 nonn,tabf,easy,less
%O A140755 1,1
%A A140755 Aldrich Stevens (aldrichstevens(AT)msn.com), May 27 2008
%E A140755 Partially edited with better definition by _Omar E. Pol_, Jan 11 2009
%E A140755 More terms from _Omar E. Pol_, Jan 11 2009