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 A380961 #26 Feb 24 2025 08:53:04 %S A380961 53,97,127,157,173,191,211,223,251,257,263,307,331,347,367,373,397, %T A380961 401,409,431,457,467,479,487,491,499,509,541,563,593,607,641,653,673, %U A380961 709,719,727,733,743,751,761,769,787,797,821,839,853,877,887,907,911,929,937,947,967,977,991,997,1009,1031,1061,1069,1103,1123 %N A380961 Primes prime(k) such that (prime(k) + prime(k+1)) mod (prime(k) - prime(k-1)) != 0. %C A380961 It seems that the proportion of primes in the sequence, among all primes, increases with larger terms (perhaps to the point where almost all primes are terms?). %H A380961 James C. McMahon, <a href="/A380961/b380961.txt">Table of n, a(n) for n = 1..10000</a> %e A380961 prime(16) = 53 is a term since (53+59) mod (53-47) != 0. %e A380961 prime(3) = 5 is not a term since (5+7) mod (5-3) = 0. %t A380961 Select[Prime[Range[2,188]],Mod[#+NextPrime[#],(#-NextPrime[#,-1])]!=0&] (* _James C. McMahon_, Feb 23 2025 *) %Y A380961 Cf. A000040, A001043, A001223. %K A380961 nonn,easy %O A380961 1,1 %A A380961 _Najeem Ziauddin_, Feb 09 2025