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A059610
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Numbers n such that 2^n-9 is prime.
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13
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4, 5, 9, 11, 17, 21, 33, 125, 141, 243, 251, 285, 321, 537, 563, 699, 729, 2841, 3365, 8451, 8577, 9699, 9725, 21011, 22689, 33921, 51761
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OFFSET
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1,1
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COMMENTS
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Except the first term 4, all terms are odd since 2^(2*m)-9 = (2^m-3) * (2^m+3) is not prime for m>2.
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LINKS
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Table of n, a(n) for n=1..27.
Search for 2^n-9, PRP Top Records
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EXAMPLE
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243 is in the sequence because 2^243-9 is prime.
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MATHEMATICA
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Select[Range[3, 20000], PrimeQ[2^#-9]&] (*From Vladimir Joseph Stephan Orlovsky, Feb 26 2011*)
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CROSSREFS
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Exponents for primes of 2^n-d form: A000043 (d=1), A050414 (d=3), A059608 (d=5), A059609 (d=7), A059610 (d=9), A096817 (d=11), A096818 (d=13), A059612 (d=15), A059611 (d=17), A096819 (d=19), A096820 (d=21)
Sequence in context: A193584 A155149 A024821 * A194154 A047610 A126004
Adjacent sequences: A059607 A059608 A059609 * A059611 A059612 A059613
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KEYWORD
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nonn,more
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AUTHOR
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Andrey V. Kulsha, Feb 02 2001
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EXTENSIONS
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a(24)-a(25) from Max Alekseyev, a(26)-a(27) from Paul Underwood, added by Max Alekseyev, Feb 09 2012
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STATUS
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approved
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