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 A283598 #32 Jun 16 2025 08:57:32
%S A283598 41,42,48,84,92,148,157,158,162,189,209,210,222,223,224,225,226,234,
%T A283598 250,306,315,316,317,318,319,326,386,387,401,407,408,433,462,487,488,
%U A283598 489,514,515,521,532,539,566,567,568,569,580,598,633,634,662,663,664,672,697,713,717,718
%N A283598 Numbers k such that all three of 6*k+1, 6*(k+1)+1, and 6*(k+2)+1 are semiprimes.
%C A283598 That is, k, k+1 and k+2 are terms in A112775.
%H A283598 Harvey P. Dale, <a href="/A283598/b283598.txt">Table of n, a(n) for n = 1..1000</a>
%t A283598 po[x_]=PrimeOmega[x];Select[Range[1000],po[6*#+1]==po[6*(1+#)+1]==po[6*(2+#)+1]==2 &]
%t A283598 Select[Range[800],PrimeOmega[6#+{1,7,13}]=={2,2,2}&] (* _Harvey P. Dale_, Apr 23 2024 *)
%Y A283598 Subsequence of A283597 and A112775.
%Y A283598 Cf. A112771, A001358.
%K A283598 nonn
%O A283598 1,1
%A A283598 _Zak Seidov_, Mar 14 2017