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 A108633 #32 Sep 20 2018 05:11:22 %S A108633 14,21,26,33,38,46,57,62,69,74,85,93,94,106,129,133,134,145,166,177, %T A108633 178,205,213,217,218,226,237,249,253,254,262,265,278,309,314,334,362, %U A108633 393,398,417,422,445,466,469,489,493,502,505,514,517,526,553,565,573,586 %N A108633 Nonsquare semiprimes with semiprime sum of factors. %C A108633 Squares of primes are not included. - _Zak Seidov_, Sep 14 2018 %H A108633 Zak Seidov, <a href="/A108633/b108633.txt">Table of n, a(n) for n = 1..1000</a> %e A108633 21 = 3*7 and 3 + 7 = 10 = 2*5. %t A108633 Select[Range[800], Plus@@Last/@FactorInteger[ # ]==Plus@@Last/@FactorInteger[(Plus@@First/@FactorInteger[ # ])]==2&] %o A108633 (PARI) is(n) = if(bigomega(n)!=2, return(0), my(f=factor(n)[, 1]~); #f==2 && bigomega(sum(i=1, #f, f[i]))==2) \\ _Felix Fröhlich_, Sep 17 2018 %Y A108633 Cf. A001358 (semiprimes), A006881 (squarefree semiprimes). %K A108633 nonn %O A108633 1,1 %A A108633 _Zak Seidov_, Jun 14 2005 %E A108633 Name clarified by _David A. Corneth_, Sep 17 2018