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.
11 is the lesser member of the prime quadruplet 5^2-2*5-4=11; 5^2-2*5-2=13; 5^2-2*5+2=17; and, 5^2-2*5+4=19.
5 is in the sequence as it generates the prime quadruplet 5^2-2*5-4=11; 5^2-2*5-2=13; 5^2-2*5+2=17; and, 5^2-2*5+4=19.
filter:= p -> andmap(isprime, [p^2-2*p-4,p^2-2*p-2,p^2-2*p+2,p^2-2*p+4]): select(filter, [seq(seq(10*i+j,j=[5,7]),i=0..10^6)]);
lista(nn) = {vk = [-2, -1, 1, 2]; for (p = 2, nn, nb = 0; for (k = 1, 4, nb += isprime(p^2-2*p+2*vk[k]);); if (nb == 4, print1(p, ", ")););} \\ Michel Marcus, Sep 26 2014
Comments