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 A112776 #24 Jul 21 2025 21:40:26 %S A112776 5,10,12,15,19,23,25,26,30,33,34,35,36,47,49,50,53,54,55,56,60,61,62, %T A112776 65,67,68,72,78,80,82,85,87,88,90,91,96,101,103,104,105,111,114,115, %U A112776 117,118,121,122,124,125,127,129,130,131,133,135,141,144,148,149,150 %N A112776 Numbers k such that 6k+5 is semiprime. %H A112776 Vincenzo Librandi, <a href="/A112776/b112776.txt">Table of n, a(n) for n = 1..1000</a> %F A112776 a(n) = (A108172(n) - 5)/6. %t A112776 Select[Range[3000], Plus@@Last/@FactorInteger[6# + 5] == 2&] (* _Vincenzo Librandi_, Sep 22 2012 *) %o A112776 (Magma) IsSemiprime:=func<n | &+[k[2]: k in Factorization(n)] eq 2>; [n: n in [2..150] | IsSemiprime(6*n+5)]; // _Vincenzo Librandi_, Sep 22 2012 %o A112776 (PARI) is(n)=bigomega(6*n+5)==2 \\ _Charles R Greathouse IV_, Feb 08 2017 %Y A112776 Cf. A108172 (resulting semiprimes). %K A112776 easy,nonn %O A112776 1,1 %A A112776 _Jonathan Vos Post_ and _Ray Chandler_, Oct 15 2005