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A163075 Primes of the form k$ + 1. Here '$' denotes the swinging factorial function (A056040). 5

%I

%S 2,3,7,31,71,631,3433,51481,2704157,280816201,4808643121,35345263801,

%T 2104098963721,94684453367401,1580132580471901,483701705079089804581,

%U 6892620648693261354601,410795449442059149332177041,2522283613639104833370312431401

%N Primes of the form k$ + 1. Here '$' denotes the swinging factorial function (A056040).

%H Jinyuan Wang, <a href="/A163075/b163075.txt">Table of n, a(n) for n = 1..50</a>

%H Peter Luschny, <a href="/A180000/a180000.pdf">Die schwingende Fakultät und Orbitalsysteme</a>, August 2011.

%H Peter Luschny, <a href="http://www.luschny.de/math/primes/SwingingPrimes.html"> Swinging Primes.</a>

%e Since 3$ = 4$ = 6 the prime 7 is listed, however only once.

%p a := proc(n) select(isprime, map(x -> A056040(x)+1,[$1..n])) end:

%t Reap[Do[f = n!/Quotient[n, 2]!^2; If[PrimeQ[p = f + 1], Sow[p]], {n, 1, 70}]][[2, 1]] // Union (* _Jean-François Alcover_, Jun 28 2013 *)

%Y Cf. A056040, A088332, A163077 (arguments k), A163074, A163076.

%K nonn

%O 1,1

%A _Peter Luschny_, Jul 21 2009

%E More terms from _Jinyuan Wang_, Mar 22 2020

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Last modified August 3 05:35 EDT 2020. Contains 336197 sequences. (Running on oeis4.)