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 A272878 #25 Aug 26 2019 05:05:40
%S A272878 1,1,2,3,8,5,16,9,26,11,30,13,32,15,34,21,44,29,46,39,50,43,60,61,64,
%T A272878 71,66,79,74,81,100,83,102,95,104,101,114,109,134,115,136,135,146,139,
%U A272878 154,141,160,143,168,155,172,165,178,173,190,177,200,189,206,199
%N A272878 a(0) = a(1) = 1, smallest a(n+1) > a(n-1) such that a(n)^2 + a(n+1)^2 is prime.
%C A272878 The associated primes 2, 5, 13, 73, 89, 281, 337, 757, 797, ... create a strictly increasing sequence. What is the rate of its growth?
%C A272878 Positive integers that are not in this sequence are 4, 6, 7, 10, 12, 14, 17, 18, 19, 20, 22, 23, 24, 25, 27, ... - _Altug Alkan_, May 14 2016
%H A272878 Amiram Eldar, <a href="/A272878/b272878.txt">Table of n, a(n) for n = 0..10000</a>
%t A272878 a[0]=1; a[1]=1; a[n_]:=a[n]= Block[{t = a[n-2] + 1}, While[! PrimeQ[t^2 + a[n-1]^2], t++]; t]; Array[a, 80, 0] (* _Giovanni Resta_, May 08 2016 *)
%o A272878 (PARI) lista(nn) = {print1(x = 1, ", "); print1(y = 1, ", "); for (n=2, nn, z = x+1; while (! isprime(y^2+z^2), z++); print1(z, ", "); x = y; y = z;);} \\ _Michel Marcus_, May 08 2016
%Y A272878 Cf. A073658, A080478, A100208.
%K A272878 nonn,look
%O A272878 0,3
%A A272878 _Thomas Ordowski_, May 08 2016
%E A272878 More terms from _Michel Marcus_, May 08 2016