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 A002641 M3352 N0446 #35 Feb 26 2022 14:42:28 %S A002641 4,9,11,23,32,39,44,51,53,60,65,72,86,93,95,114,123,156,170,179,186, %T A002641 200,207,212,219,228,233,240,249,261,270,303,317,333,338,345,375,389, %U A002641 401,443,452,473,480,492,515,534,548,564,578,585,597,599,611,641,660,662 %N A002641 Numbers k such that (k^2 + k + 1)/7 is prime. %D A002641 A. J. C. Cunningham, Binomial Factorisations, Vols. 1-9, Hodgson, London, 1923-1929; see Vol. 1, pp. 245-259. %D A002641 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A002641 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A002641 Vincenzo Librandi, <a href="/A002641/b002641.txt">Table of n, a(n) for n = 1..1000</a> %H A002641 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 A002641 Select[Range[700], PrimeQ[(#^2 + # + 1)/7] &] (* _Harvey P. Dale_, Sep 16 2011 *) %o A002641 (Magma) /* See Crossrefs: */ %o A002641 A047348:=[m: m in [1..700] | m mod 7 in [2,4]]; %o A002641 [n: n in A047348 | IsPrime( (n^2+n+1) div 7 )]; %o A002641 // _Bruno Berselli_, Sep 26 2012 %o A002641 (PARI) is(n)=isprime((n^2+n+1)/7) \\ _Charles R Greathouse IV_, May 22 2017 %Y A002641 Subsequence of A047348. %K A002641 nonn,easy %O A002641 1,1 %A A002641 _N. J. A. Sloane_ %E A002641 More terms from _Jon E. Schoenfield_, Mar 24 2010