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 A130588 #7 Jun 16 2019 22:30:10 %S A130588 2,3,4,5,6,7,8,9,12,16,18,24,26,28,36,42,60,84,90,96,114,300 %N A130588 Integers which are not the sum of a 3-almost prime and a prime. %C A130588 T. D. Noe found no more values up to 10000 and agrees with my conjecture that this sequence is probably finite. This is related to Chen's Theorem: "Every 'large' even number may be written as 2n = p + m where p is a prime and m in A001358 is the set of semiprimes (i.e., 2-almost primes)" which itself is related to Goldbach's conjecture. However, we have no proof, merely the sense that it gets easier and easier to find more and more A014612(i) + A000040(j) = n decompositions as n increases. %F A130588 {n such that for no integers i, j is it the case that A014612(i) + A000040(j) = n}. %e A130588 n<10 are in this sequence because the smallest 3-almost prime is 8, hence the smallest 3-almost prime plus prime is 10 = 8 + 2. We have that 282 is not in this sequence because 282 = 125 + 157 = A014612(30) + A000040(37). %t A130588 Rest@Complement[Range[1000], Union@Flatten@Outer[Plus, Select[Range[1000], PrimeOmega[#] == 3 &], Prime[Range[PrimePi[1000]]]]] (* _Robert Price_, Jun 16 2019 *) %Y A130588 Cf. A000040, A001358, A014612, A064653. %K A130588 more,nonn,fini %O A130588 2,1 %A A130588 _Jonathan Vos Post_, Jun 16 2007