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 A176100 #11 Feb 20 2017 23:19:20 %S A176100 0,2,8,12,16,18,20,24,28,30,32,36,40,42,44,48,50,52,54,56,60,64,66,68, %T A176100 70,72,76,78,80,84,88,90,92,96,98,100,102,104,108,110,112,114,116,120, %U A176100 124,126,128,130,132,136,138,140,144,148,150,152,154,156,160,162,164 %N A176100 Even numbers that are not semiprimes, or, twice the nonprimes. %F A176100 a(n)= 2*A141468(n). %F A176100 A005843 \ A100484. %F A176100 a(n) = A139270(n-1). [_R. J. Mathar_, May 03 2010] %t A176100 2 Prepend[Select[Range@ 82, ! PrimeQ@ # &], 0] (* _Michael De Vlieger_, Feb 20 2017 *) %o A176100 (PARI) isok(n) = !(n%2) && !isprime(n/2); \\ _Michel Marcus_, Feb 20 2017 %Y A176100 Cf. A001358, A005843, A100484, A141468. %K A176100 nonn,easy %O A176100 1,2 %A A176100 _Juri-Stepan Gerasimov_, Apr 08 2010, Apr 11 2010 %E A176100 Entries checked by _R. J. Mathar_, Apr 16 2010