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A138030 Numbers n such that n remains prime through 8 iterations of function f(x) = 2x + 1. 0
85864769, 198479579, 305192579 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

MATHEMATICA

Select[Prime[Range[10^8]], PrimeQ[a1=2*#+1]&&PrimeQ[a2=2*a1+1]&&PrimeQ[a3=2*a2+1]&&PrimeQ[a4=2*a3+1]&&PrimeQ[a5=2*a4+1]&&PrimeQ[a6=2*a5+1]&&PrimeQ[a7=2*a6+1]&&PrimeQ[a8=2*a7+1] &]

CROSSREFS

Sequence in context: A186922 A185806 A115534 * A104964 A018787 A003825

Adjacent sequences:  A138027 A138028 A138029 * A138031 A138032 A138033

KEYWORD

nonn,bref

AUTHOR

Vladimir Orlovsky (4vladimir(AT)gmail.com), May 01 2008

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Last modified February 14 08:58 EST 2012. Contains 205614 sequences.