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A163083 Primes of the form n$ + 1 which are the greater of twin primes. Here '$' denotes the swinging factorial function (A056040). 2
7, 31, 51481, 1580132580471901 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A163075 and of A006512.

LINKS

Table of n, a(n) for n=1..4.

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-Fran├žois Alcover, Jul 29 2013 *)

CROSSREFS

Cf. A163075, A006512.

Sequence in context: A191297 A134709 A139314 * A101329 A193637 A214490

Adjacent sequences:  A163080 A163081 A163082 * A163084 A163085 A163086

KEYWORD

nonn

AUTHOR

Peter Luschny, Jul 21 2009

STATUS

approved

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Last modified June 26 23:21 EDT 2017. Contains 288777 sequences.