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 A117531 #13 Apr 19 2025 14:39:20
%S A117531 1,2,3,3,5,3,7,3,5,6,6,6,13,3,11,8,12,8,13,10,8,7,12,10,9,21,6,22,11,
%T A117531 7,13,12,21,13,14,16,18,7,20,17,21,20,24,14,18,20,16,16,35,10,18,29,
%U A117531 18,30,30,26,21,18,21,29,16,22,32,40,10,27,24,25,45,18,39,40,43,11,11
%N A117531 Number of primes in the n-th row of the triangle in A117530.
%C A117531 1 <= a(n) <= n; conjecture: a(n) < n for n>13.
%H A117531 Robert Price, <a href="/A117531/b117531.txt">Table of n, a(n) for n = 1..10000</a>
%F A117531 a(n) = Sum_{k=1..n} A010051(A117530(n,k)).
%t A117531 Function[Count[#, _?PrimeQ]] /@ Table[k^2 - k + Prime[n], {n, 100}, {k, n}] (* _Robert Price_, Apr 19 2025 *)
%Y A117531 Cf. A010051, A117530.
%K A117531 nonn
%O A117531 1,2
%A A117531 _Reinhard Zumkeller_, Mar 25 2006