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 A087716 #13 Apr 14 2021 05:24:12 %S A087716 341,1387,2047,4681,13747 %N A087716 Base-2 pseudoprimes (see A001567) of the form j*p(i)# - p(k) or j*p(i)# + p(k), p(i) and p(k) primes with p(i) < p(k) < p(i+1)^2 and 0 < j < p(i+1). %C A087716 Conjecture: sequence has only 5 terms. This has been checked for all i <= 150. %H A087716 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a> %e A087716 2*7# - 79 = 341, %e A087716 7*7# - 83 = 1387, %e A087716 10*7# - 53 = 2047, %e A087716 2*11# + 61 = 4681, %e A087716 6*11# - 113 = 13747, %e A087716 13*7# - 29 = 2701. %o A087716 (PARI) lst(lim)=my(p=2,P=1,v=List());forprime(q=3,lim,P*=p;forprime(r=q, q^2, for(j=1,q-1,if(j*P-r>340&&psp(j*P-r),listput(v,j*P-r)); if(psp(j*P+r),listput(v,j*P+r))));p=q);vecsort(Vec(v),,8) \\ _Charles R Greathouse IV_, Apr 12 2012 %Y A087716 Cf. A001567, A087714, A087715, A087728. %Y A087716 # denotes primorials; see A002110. %K A087716 nonn,more %O A087716 1,1 %A A087716 _Pierre CAMI_, Sep 29 2003 %E A087716 Edited by _David Wasserman_, Apr 13 2006