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 A180441 #4 Jul 22 2025 08:27:45 %S A180441 113,131,139,173,233,421,953,1013,1021,1051,1583,1747,1901,2099,2423, %T A180441 2579,2819,2939,3761,3779,3931,4211,4253,4451,4591,5003,5861,5903, %U A180441 6427,6691,6949,7079,7481,7541,7717,8263,8783,8831,9127,9227,9413,9923,10061 %N A180441 First term of four consecutive primes whose average is a prime. %F A180441 a(n)=[p(n)+p(n+1)+p(n+2)+p(n+3)]/4 a(n) being a prime %e A180441 a(5)=233 since (233+239+241+251)/4=964/4=241 is a prime. %Y A180441 Cf. A000040, A122535 %K A180441 nonn %O A180441 1,1 %A A180441 _Carmine Suriano_, Sep 05 2010