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 A163080 #10 May 08 2020 17:43:45 %S A163080 3,5,7,13,41,47,83,137,151,229,317,389,1063,2371,6101,7873,13007,19603 %N A163080 Primes p such that p$ - 1 is also prime. Here '$' denotes the swinging factorial function (A056040). %C A163080 a(n) are the primes in A163078. %H A163080 Peter Luschny, <a href="/A180000/a180000.pdf">Die schwingende Fakultät und Orbitalsysteme</a>, August 2011. %H A163080 Peter Luschny, <a href="http://www.luschny.de/math/primes/SwingingPrimes.html"> Swinging Primes.</a> %e A163080 3 is prime and 3$ - 1 = 5 is prime, so 3 is in the sequence. %p A163080 a := proc(n) select(isprime,select(k -> isprime(A056040(k)-1),[$0..n])) end: %t A163080 sf[n_] := n!/Quotient[n, 2]!^2; Select[Prime /@ Range[200], PrimeQ[sf[#] - 1] &] (* _Jean-François Alcover_, Jun 28 2013 *) %o A163080 (PARI) is(k) = isprime(k) && ispseudoprime(k!/(k\2)!^2-1); \\ _Jinyuan Wang_, Mar 22 2020 %Y A163080 Cf. A056040, A103317, A163079, A163078. %K A163080 nonn,more %O A163080 1,1 %A A163080 _Peter Luschny_, Jul 21 2009 %E A163080 a(14)-a(18) from _Jinyuan Wang_, Mar 22 2020