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 A054775 #13 Sep 08 2022 08:45:01 %S A054775 24,36,48,54,66,78,84,90,96,114,120,126,132,144,156,162,168,174,186, %T A054775 204,210,216,222,234,246,252,258,264,276,288,294,300,306,318,324,330, %U A054775 336,342,354,360,366,372,378,384,390,396,402,408,414,426,438,444,450,456,468,474 %N A054775 Positive multiples of 6 which are not the midpoint of a pair of twin primes. %o A054775 (Magma) [ n: n in [6..600 by 6] | not IsPrime(n-1) or not IsPrime(n+1) ]; // _Klaus Brockhaus_, Aug 18 2010 %o A054775 (PARI) forstep(n=6,600,6,if(!(isprime(n-1)&&isprime(n+1)),print1(n,","))) \\ _Klaus Brockhaus_, Aug 18 2010 %Y A054775 Cf. A067611 (sequence divided by 6). %K A054775 nonn %O A054775 1,1 %A A054775 Stuart M. Ellerstein (ellerstein(AT)aol.com), May 19 2000 %E A054775 Corrected by _Zak Seidov_ and _Klaus Brockhaus_, Aug 18 2010 %E A054775 Edited by _N. J. A. Sloane_, Aug 19 2010