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 A002644 M5000 N1426 #27 Oct 18 2023 10:04:17 %S A002644 16,25,37,46,58,88,109,130,142,151,184,193,205,247,268,298,310,319, %T A002644 331,340,382,394,403,415,424,457,478,487,541,550,604,613,688,697,709, %U A002644 730,739,751,760,793,844,865,886,907,970,1012,1045,1054,1066,1117,1138 %N A002644 Numbers k such that (k^2 + k + 1)/21 is prime. %D A002644 A. J. C. Cunningham, Binomial Factorisations, Vols. 1-9, Hodgson, London, 1923-1929; see Vol. 1, pp. 245-259. %D A002644 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A002644 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A002644 Vincenzo Librandi, <a href="/A002644/b002644.txt">Table of n, a(n) for n = 1..1000</a> %H A002644 A. J. C. Cunningham, <a href="/A001912/a001912.pdf">Binomial Factorisations</a>, Vols. 1-9, Hodgson, London, 1923-1929. [Annotated scans of a few pages from Volumes 1 and 2] %t A002644 Select[Range[1200], PrimeQ[(#^2 + # + 1)/21] &] (* _Vincenzo Librandi_, Sep 25 2012 *) %o A002644 (PARI) is(n)=isprime((n^2+n+1)/21) \\ _Charles R Greathouse IV_, Jun 06 2017 %K A002644 nonn,easy %O A002644 1,1 %A A002644 _N. J. A. Sloane_ %E A002644 More terms from Larry Reeves (larryr(AT)acm.org), Sep 21 2000