OFFSET
1,1
COMMENTS
# denotes primorial; k >= 1.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..300
EXAMPLE
a(4)=431 because prime(4)#*2+prime(5) = 431 is prime.
MATHEMATICA
lp[{a_, b_}]:=Module[{k=1}, While[!PrimeQ[k*a+b], k++]; k*a+b]; With[{nn=20}, lp/@Thread[ {FoldList[Times, Prime[Range[nn]]], Prime[Range[2, nn+1]]}]] (* Harvey P. Dale, Dec 25 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Jan 21 2004
EXTENSIONS
Edited by Don Reble, May 07 2006
STATUS
approved