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 A070092 #9 May 14 2019 22:09:32
%S A070092 0,0,0,0,0,1,1,1,1,0,1,1,1,0,1,1,2,0,1,0,1,0,0,1,2,0,2,1,2,0,1,0,2,0,
%T A070092 1,1,2,0,3,1,3,0,2,0,3,0,1,1,3,0,3,0,2,0,1,0,3,0,1,1,2,0,3,1,4,0,2,0,
%U A070092 4,0,1,0,1,0,4,1,3,0,2,0,3,0,1,1,3,0,4,1,4,0
%N A070092 Number of isosceles integer triangles with perimeter n and prime side lengths.
%H A070092 R. Zumkeller, <a href="/A070080/a070080.txt">Integer-sided triangles</a>
%F A070092 a(n) = A070088(n) - A070090(n).
%F A070092 a(n) = Sum_{k=1..floor(n/3)} Sum_{i=k..floor((n-k)/2)} sign(floor((i+k)/(n-i-k+1))) * ([i = k] + [i = n-i-k] - [k = n-i-k]) * A010051(i) * A010051(k) * A010051(n-i-k), where [] is the Iverson bracket. - _Wesley Ivan Hurt_, May 14 2019
%e A070092 For n=17 there are A005044(17)=8 integer triangles: [1,8,8], [2,7,8], [3,6,8], [3,7,7], [4,5,8], [4,6,7], [5,5,7] and [5,6,6]: four are isosceles: [1<8=8], [3<7=7], [5=5<7] and [5<6=6], but only two of them consist of primes, therefore a(17)=2.
%t A070092 Table[Sum[Sum[(PrimePi[i] - PrimePi[i - 1]) (PrimePi[k] - PrimePi[k - 1]) (PrimePi[n - i - k] - PrimePi[n - i - k - 1]) (KroneckerDelta[i, k] + KroneckerDelta[i, n - i - k] - KroneckerDelta[k, n - i - k]) Sign[Floor[(i + k)/(n - i - k + 1)]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}], {n, 100}] (* _Wesley Ivan Hurt_, May 14 2019 *)
%Y A070092 Cf. A070080, A070081, A070082, A059169, A070100, A070108, A070117.
%K A070092 nonn
%O A070092 1,17
%A A070092 _Reinhard Zumkeller_, May 05 2002