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I was examining primes q that are q=(n+1)pnp with p also prime. There seems to be more than one solution for most n. In the table below all the first solutions of p up to 2000 and for n up to 200:

npnpnpnp13512910151515923523102131521583335347910371533435451045154435555310531557635619106156377575107591573875831083158393591095159710360110516013113611711111316171217623112516238913363311316347143645114139164315436571152691653165663116166131736731177167167181607681711813168111956911119316917201970471205170321127716112151713222297219122717232337323123317319243743124174525375512531753261376191264117637273777127591772692837851283178529149797129317933038031301499180193158131311011814332382331132167182433323834113318311343841791347184335585513571853368386313631863373875137187383883138113188133937891091391894140790314031905341391314171913423921714231925433793314319334459461144519445395314571953465961307146131963479771473197548398709148519849399514927119931507100431501320059
47 is the first n that has no solution for p<2000. I tried n=47 for higher p but still no solution for p<10000

Question: Is there a way to prove that q=48p47p is never prime? After factoring 48p47p for several p, I found the smallest prime factor is always 1(modp) but I don't see how this helps.

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  • Sorry but where are the mathematics in "Q.: Is there some integer p such that property P holds?" "A.: Yes, because the OEIS says so"? Commented Apr 12, 2017 at 13:58
  • @Did OEIS says so because people have calculated to that number and found that for p=58543, the property P holds. Commented Apr 12, 2017 at 14:09
  • @DHMO No kidding? Of course they have. And where should I feel enlightened (mathematically speaking) by this question and by your (technically accurate) answer? Commented Apr 12, 2017 at 14:18
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    @Did Nowhere at all. Commented Apr 12, 2017 at 14:20
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    Still formulated otherwise: the question is tagged (number-theory), I see the numbers but not the theory. Commented Apr 12, 2017 at 14:23

1 Answer 1

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According to A125713, n=58543 corresponds to a prime.

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