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 A172462 #6 Jan 21 2019 23:17:08 %S A172462 59,60,61,72,93,102,103,108,109,123,144,149,150,151,161,162,163,171, %T A172462 207,213,236,237,257,258,264,265,266,267,268,276,291,312,313,318,333, %U A172462 334,348,357,389,390,391,396,401,402,408,417,422,423,424,434,435,436,446 %N A172462 Numbers k such that 2k-3, 2k-1, 2k+1 and 2k+3 are composite. %C A172462 Almost all numbers are in this sequence, by the Prime Number Theorem. %e A172462 a(1)=59 because 2*59-1=117, 2*59+1=119, 2*59-3=115 and 2*59+3=121 are all composite. %p A172462 a := proc (n): if isprime(2*n-3) = false and isprime(2*n-1) = false and isprime(2*n+1) = false and isprime(2*n+3) = false then n else end if end proc: seq(a(n), n = 1 .. 500); # _Emeric Deutsch_, Feb 15 2010 %Y A172462 Cf. A104278. %K A172462 nonn,easy,less %O A172462 1,1 %A A172462 _Juri-Stepan Gerasimov_, Feb 03 2010 %E A172462 Corrected and extended by _Emeric Deutsch_, Feb 15 2010 %E A172462 Comment from _Charles R Greathouse IV_, Mar 25 2010