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 A238397 #10 Feb 27 2014 14:40:34
%S A238397 31,41,59,61,71,87,91,101,103,113,119,121,129,131,143,151,161,167,171,
%T A238397 185,191,199,211,213,215,221,227,239,241,243,247,251,263,269,271,275,
%U A238397 281,293,297,299,301,311,321,327,331,339,341,343,347,355
%N A238397 Numbers of the form pq + qr + rp where p, q and r are distinct primes (sorted sequence without duplicates).
%C A238397 Numbers of the form e2(p, q, r) for distinct primes p, q, r, where e2 is the elementary symmetric polynomial of degree 2. Other sequences are obtained with different numbers of distinct primes and degrees: A000040 for 1 prime, A038609 and A006881 for 2 primes, A124867, this sequence, and A007304 for 3 primes. The 4-prime sequences are not presently in the OEIS with the exception of A046386. - _Charles R Greathouse IV_, Feb 26 2014
%H A238397 Jean-François Alcover, <a href="/A238397/b238397.txt">Table of n, a(n) for n = 1..1000</a>
%e A238397 71 = 3*5 + 5*7 + 7*3 = 2*3 + 3*13 + 13*2 is in the sequence (only once, though 2 solutions exist).
%t A238397 terms = 50; dm (* initial number of primes *) = 10; f[p_, q_, r_] := p*q + q*r + r*p; Clear[A238397]; A238397[m_] := A238397[m] = Take[u = Union[f @@@ Subsets[Prime /@ Range[m], {3}]], Min[Length[u], terms]]; A238397[dm]; A238397[m = 2*dm]; While[Print["m = ", m]; A238397[m] != A238397[m - dm], m = m + dm]; A238397[m]
%o A238397 (PARI) is(n)=forprime(r=(sqrtint(3*n-3)+5)\3, (n-6)\5, forprime(q= sqrtint(r^2+n)-r+1, min((n-2*r)\(r+2), r-2), if((n-q*r)%(q+r)==0 && isprime((n-q*r)/(q+r)), return(1)))); 0 \\ _Charles R Greathouse IV_, Feb 26 2014
%o A238397 (PARI) list(n)=my(v=List()); forprime(r=5, (n-6)\5, forprime(q=3, min((n-2*r)\(r+2), r-2), my(S=q+r, P=q*r); forprime(p=2, min((n-P)\S, q-1), listput(v, p*S+P)))); Set(v) \\ _Charles R Greathouse IV_, Feb 26 2014
%Y A238397 Cf. A087053, A087054.
%K A238397 nonn
%O A238397 1,1
%A A238397 _Jean-François Alcover_, Feb 26 2014