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 A133520 #7 May 17 2015 17:43:21 %S A133520 1,2,6,10,12,10,16,16,6,12,18,16,12,28,6,22,6,16,6,16,6,16,30,6,16,42, %T A133520 22,42,28,52,22,16,28,10,28,70,30,42,78,36,12,42,6,12,40,12,12,16,16, %U A133520 16,18,10,6,22,60,46,76,46,18,126,12,22,22,6,16,16,22,18,120,22,12,6,6,36 %N A133520 Smallest k such that p(n)^4 + k is prime where p(n) is the n-th prime. %H A133520 Harvey P. Dale, <a href="/A133520/b133520.txt">Table of n, a(n) for n = 1..1000</a> %e A133520 p(2)=3, 3^4 = 81; for odd k and n > 1, p(n)^r + k is even and thus not prime, so we only need consider even k. %e A133520 for k = 2: 81 + 2 = 83, which is prime, so 2 is the smallest number that can be added to 81 to make a new prime. %e A133520 Hence a(2) = 2. %t A133520 NextPrime[#]-#&/@(Prime[Range[80]]^4) (* _Harvey P. Dale_, May 17 2015 *) %Y A133520 Cf. A030814, A054271, A091666, A133517, A133518, A133519, A133521, A133522, (A001223). %K A133520 easy,nonn %O A133520 1,2 %A A133520 _Carl R. White_, Sep 14 2007