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 A055003 #13 Aug 08 2017 10:58:27 %S A055003 2,3,7,13,29,37,53,61,79,107,113,151,173,181,199,239,271,281,317,349, %T A055003 359,397,421,457,503,541,557,577,593,613,701,733,769,787,857,863,911, %U A055003 953,983,1021,1061,1069,1151,1163,1193,1213,1291,1399,1429 %N A055003 a(n) = prime(prime(n)-1). %p A055003 with(numtheory): [seq(ithprime(ithprime(i)-1),i=1..70)]; %o A055003 (PARI) a(n) = prime(prime(n)-1); \\ _Michel Marcus_, Aug 08 2017 %Y A055003 Cf. A000040, A008578. %K A055003 nonn %O A055003 1,1 %A A055003 _N. J. A. Sloane_, Jun 10 2000