

A163079


Primes p such that p$ + 1 is also prime. Here '$' denotes the swinging factorial function (A056040).


4



2, 3, 5, 31, 67, 139, 631, 9743, 16253, 17977, 27901, 37589
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OFFSET

1,1


COMMENTS

a(n) are the primes in A163077.


REFERENCES

Peter Luschny, "Divide, swing and conquer the factorial and the lcm{1,2,...,n}", preprint, April 2008.


LINKS

Table of n, a(n) for n=1..12.
Peter Luschny, Swinging Primes.


EXAMPLE

5 is prime and 5$ + 1 = 30 + 1 = 31 is prime, so 5 is in the sequence.


MAPLE

a := proc(n) select(isprime, select(k > isprime(A056040(k)+1), [$0..n])) end:


MATHEMATICA

f[n_] := 2^(n  Mod[n, 2])*Product[k^((1)^(k + 1)), {k, n}]; p = 2; lst = {}; While[p < 38000, a = f@p + 1; If[ PrimeQ@a, AppendTo[ lst, p]; Print@p]; p = NextPrime@p]; lst (* Robert G. Wilson v, Aug 08 2010 *)


CROSSREFS

Cf. A163077, A062363, A093804, A002981.
Cf. A056040.  Robert G. Wilson v, Aug 09 2010
Sequence in context: A265807 A106308 A036797 * A109845 A241722 A276043
Adjacent sequences: A163076 A163077 A163078 * A163080 A163081 A163082


KEYWORD

nonn,more


AUTHOR

Peter Luschny, Jul 21 2009


EXTENSIONS

a(8)  a(12) from Robert G. Wilson v, Aug 08 2010


STATUS

approved



