

A111296


Smallest prime of the form n*k + 1, where each k may be used in the sequence only once.


1



2, 5, 13, 13, 31, 31, 71, 73, 73, 71, 199, 157, 157, 197, 241, 241, 409, 199, 419, 401, 547, 419, 691, 409, 701, 547, 919, 701, 929, 691, 1117, 929, 1321, 919, 1471, 1117, 1777, 1483, 1483, 1321, 2297, 1471, 1979, 2069, 2251, 1979, 2069, 1777, 2549, 2251
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..50.


EXAMPLE

a(10) = 10*13 + 1 = 131 though 10*10 + 1 = 101 is also prime but k=10 has already been used by n=7.


MATHEMATICA

l = {}; Do[k = 1; While[MemberQ[l, k]  !PrimeQ[n*k + 1], k++ ]; Print[n*k+1]; AppendTo[l, k], {n, 30}] (* Ryan Propper, Jun 15 2006 *)


CROSSREFS

Cf. A087559.
Sequence in context: A067365 A189993 A112838 * A089728 A127987 A247543
Adjacent sequences: A111293 A111294 A111295 * A111297 A111298 A111299


KEYWORD

nonn


AUTHOR

Amarnath Murthy, Nov 11 2005


EXTENSIONS

Corrected and extended by Ryan Propper, Jun 15 2006
More terms from R. J. Mathar, Aug 20 2007


STATUS

approved



