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 A188424 #12 Apr 14 2018 13:09:21 %S A188424 1,2,4,4,2,10,4,3,16,6,5,10,10,5,13,14,3,10,16,7,40,8,6,26,12,9,19,14, %T A188424 9,34,21,5,19,36,13,28,18,7,31,18,19,34,15,14,27,27,11,41,31,11,68,16, %U A188424 10,71,30,20,23,21,16,40,40,13,57,37,23,37,24,16,67,44,16,41,20,20,54,55,12,43,54,15,81,26,15,65,34,37,50,20,29,70,68,14,52,46,14,79,43,18,60,70 %N A188424 Number of primes of the form k^2 + k + 2n - 1 for k = 0..2n-1. %H A188424 Seiichi Manyama, <a href="/A188424/b188424.txt">Table of n, a(n) for n = 1..5000</a> %e A188424 a(21) = 40 because the polynomial k^2 + k + 41 generates 40 distinct primes for k = 0, 1, .., 39. %p A188424 with(numtheory):for n from 1 by 2 to 200 do:m:=0:for k from 0 to n do: x:=k^2+k+n:if %p A188424 type(x,prime)=true then m:=m+1:else fi:od:printf(`%d, `,m):od: %Y A188424 Cf. A005846, A056561. %K A188424 nonn %O A188424 1,2 %A A188424 _Michel Lagneau_, Mar 30 2011