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 A128277 #8 Jan 01 2024 02:27:31 %S A128277 93081,449985,1523705,301921991,899343761,1581262341,7290929465, %T A128277 12102153569,25404516309,27482957831,38661868781,49656488021, %U A128277 240305617889,305000299185,341656377581,377737353491 %N A128277 a(n) is the n-th smallest integer m which is the product of 4 odd primes m=p1*p2*p3*p4 such that d+2*m/d are all primes for each d dividing 2*m. %C A128277 1. a(6) > 2*10^9 %C A128277 2. (C. Pomerance) The prime k-tuple conjecture implies the sequence is infinite. %C A128277 a(17) > 4*10^11. - _Donovan Johnson_, Sep 06 2010 %e A128277 93081 = 3*19*23*71 and 2*93081+1, 2+3*19*23*71, 3+2*19*23*71, 19+2*3*23*71, 71+2*3*19*23, 2*3+19*23*71, 2*19+3*23*71, 2*23+3*19*23*71, 2*71+3*19*23, 3*19+2*23*71, 3*23+2*19*71, 3*71+2*19*23, 19*23+2*3*71, 19*71+2*3*23, 23*71+2*3*19 are all primes and 93081 is smallest such integer, so a(1)=93081. %Y A128277 Cf. A128276. %K A128277 hard,more,nonn %O A128277 1,1 %A A128277 Kok Seng Chua (chuakokseng(AT)hotmail.com), Feb 23 2007 %E A128277 Changed every occurrence of 93801 to 93081. - _T. D. Noe_, Aug 05 2010 %E A128277 Added missing term 899343761 and a(7)-a(16) from _Donovan Johnson_, Sep 06 2010