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 A192220 #13 Jan 23 2025 03:40:17
%S A192220 4,6,9,34,51,55,86,94,129,142,183,185,202,214,218,247,249,302,341,394,
%T A192220 415,446,471,473,535,583,634,698,723,737,807,851,905,922,926,949,1042,
%U A192220 1138,1149,1205,1211,1241,1257,1262,1313,1315,1337,1346,1402,1527,1546,1577,1594,1642,1646,1673,1687
%N A192220 Semiprimes s such that tau(s-1) = tau(s+1) where tau = A000005.
%H A192220 Amiram Eldar, <a href="/A192220/b192220.txt">Table of n, a(n) for n = 1..10000</a>
%F A192220 A001358 INTERSECT A067888.
%t A192220 Select[Range[2000], PrimeOmega[#] == 2 && Equal @@ DivisorSigma[0, # + {-1, 1}] &] (* _Amiram Eldar_, Jan 23 2025 *)
%o A192220 (PARI) isok(k) = bigomega(k) == 2 && numdiv(k-1) == numdiv(k+1); \\ _Amiram Eldar_, Jan 23 2025
%Y A192220 Cf. A000005, A001358, A067888, A067889.
%K A192220 nonn
%O A192220 1,1
%A A192220 _Juri-Stepan Gerasimov_, Jun 26 2011