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 A100319 #52 Apr 10 2019 21:10:51 %S A100319 8,10,14,16,20,22,24,26,28,32,34,36,38,40,44,46,48,50,52,54,56,58,62, %T A100319 64,66,68,70,74,76,78,80,82,84,86,88,90,92,94,96,98,100,104,106,110, %U A100319 112,114,116,118,120,122,124,126,128,130,132,134,136,140,142,144,146,148 %N A100319 Even numbers m such that at least one of m-1 and m+1 is composite. %C A100319 Subsequence of A100318. For each k >= 0, a(k+1) = a(k) + 2 unless a(k) + 1 and a(k) + 3 are twin primes, in which case a(k+1) = a(k) + 4 (as a(k) - 1 and a(k) + 5 are divisible by 3). %C A100319 The even nonisolated primes(n+1). - _Juri-Stepan Gerasimov_, Nov 09 2009 %H A100319 G. C. Greubel, <a href="/A100319/b100319.txt">Table of n, a(n) for n = 1..1000</a> %F A100319 a(n) = A167692(n+1). - _Juri-Stepan Gerasimov_, Nov 09 2009 %t A100319 Select[2*Range[100], CompositeQ[#-1] || CompositeQ[#+1] &] (* _G. C. Greubel_, Mar 09 2019 *) %o A100319 (PARI) forstep(n=4,300,2,if(isprime(n-1)+isprime(n+1)<=1,print1(n,","))) %o A100319 (Sage) [n for n in (3..250) if mod(n,2)==0 and (is_prime(n-1) + is_prime(n+1)) < 2] # _G. C. Greubel_, Mar 09 2019 %Y A100319 Cf. A100318 (supersequence containing odd and even n), A045718 (n such that at least one of n-1 and n+1 is prime). %Y A100319 Cf. A167692(the even nonisolated nonprimes). - _Juri-Stepan Gerasimov_, Nov 09 2009 %Y A100319 Cf. A005818, A038179, A007310, A038511, A025584. %Y A100319 Complement of A014574 (average of twin prime pairs) w.r.t. A005843 (even numbers), except for missing term 2. %K A100319 nonn %O A100319 1,1 %A A100319 _Rick L. Shepherd_, Nov 13 2004