cp's OEIS Frontend

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.

A057705 Primorial primes: primes p such that p+1 is a primorial number (A002110).

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%I A057705 #41 Feb 01 2024 00:27:03
%S A057705 5,29,2309,30029,304250263527209,23768741896345550770650537601358309,
%T A057705 19361386640700823163471425054312320082662897612571563761906962414215012369856637179096947335243680669607531475629148240284399976569
%N A057705 Primorial primes: primes p such that p+1 is a primorial number (A002110).
%H A057705 Chris K. Caldwell's The Top Twenty, <a href="https://t5k.org/top20/page.php?id=5">Primorial</a>.
%H A057705 Romeo Mestrovic, <a href="https://arxiv.org/abs/1202.3670">Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof</a>, arXiv preprint arXiv:1202.3670 [math.HO], 2012. - _N. J. A. Sloane_, Jun 13 2012
%F A057705 a(n) = A002110(A057704(n)) - 1.
%t A057705 Select[FoldList[Times, 1, Prime[Range[70]]], PrimeQ[# - 1] &] - 1 (* _Harvey P. Dale_, Jan 27 2014 *)
%o A057705 (Haskell)
%o A057705 a057705 n = a057705_list !! (n-1)
%o A057705 a057705_list = filter ((== 1) . a010051) a057588_list
%o A057705 -- _Reinhard Zumkeller_, Mar 27 2013
%Y A057705 See A006794 and A057704 (the main entries for this sequence) for more terms.
%Y A057705 Cf. A014545, A018239.
%Y A057705 Cf. A002110, A010051.
%Y A057705 Subsequence of A057588.
%K A057705 nonn,nice
%O A057705 1,1
%A A057705 _Labos Elemer_, Oct 24 2000