A163083 Primes of the form k$ + 1 which are the greater of twin primes. Here '$' denotes the swinging factorial function (A056040).

7, 31, 51481, 1580132580471901

Offset

1,1

Comments

Subsequence of A163075 and of A006512.

Links

Jinyuan Wang, Table of n, a(n) for n = 1..5

Peter Luschny, Swinging Primes.

Maple

a := proc(n) select(s->isprime(s) and isprime(s-2), map(k -> A056040(k)+1, [$4..n])) end:

Mathematica

sf[n_] := With[{f = Floor[n/2]}, Pochhammer[f+1, n-f]/f!]; Do[ If[ PrimeQ[p = sf[n] + 1] && PrimeQ[p - 2], Print["n = ", n, " p = ", p]], {n, 1, 400}] (* Jean-François Alcover, Jul 29 2013 *)

Crossrefs

Cf. A056040, A006512, A163075.

Sequence in context: A134709 A139314 A290969 * A101329 A193637 A214490

Adjacent sequences: A163080 A163081 A163082 * A163084 A163085 A163086

Keyword

nonn

Author

Peter Luschny, Jul 21 2009

Status

approved