

A260388


a(1)=2; thereafter a(n) is the smallest prime > a(n1) that is not a factor of any 1+A, where A is a product of one or more distinct earlier terms.


2



2, 5, 7, 13, 17, 29, 53, 89, 199, 271, 349, 823, 1747, 2251, 2593, 6569, 7121, 27479, 44129, 85361, 115259, 254731, 462103, 903751
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..24.
Anders Hellström, Ruby program


MATHEMATICA

L={2}; While[Length@L < 15, s= LCM@@ (1 + Times @@@ Subsets[L]); p = NextPrime@ L[[1]]; While[ Mod[s, p] == 0, p = NextPrime@ p]; AppendTo[L, p]]; L (* inefficient, Giovanni Resta, Aug 19 2015 *)


CROSSREFS

Sequence in context: A082555 A160794 A092059 * A169586 A023229 A176983
Adjacent sequences: A260385 A260386 A260387 * A260389 A260390 A260391


KEYWORD

nonn,hard,more


AUTHOR

Anders Hellström, Aug 18 2015


EXTENSIONS

a(14)a(24) from Giovanni Resta, Aug 19 2015


STATUS

approved



