

A059610


Numbers n such that 2^n  9 is prime.


16



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, 655845, 676761
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OFFSET

1,1


COMMENTS

Except the first term 4, all terms are odd since 2^(2*m)  9 = (2^m3) * (2^m+3) is not prime for m>2.


LINKS

Table of n, a(n) for n=1..29.
Keith Conrad, Square patterns and infinitude of primes, University of Connecticut, 2019.
Henri Lifchitz & Renaud Lifchitz (Editors), Search for 2^n9, PRP Top Records


EXAMPLE

243 is in the sequence because 2^243  9 is prime.


MATHEMATICA

Select[Range[3, 20000], PrimeQ[2^#9]&] (* Vladimir Joseph Stephan Orlovsky, Feb 26 2011 *)


PROG

(PARI) is(n)=isprime(2^n9) \\ Charles R Greathouse IV, Feb 17 2017


CROSSREFS

Exponents for primes of the form 2^n  d: 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 * A341783 A319606 A230239
Adjacent sequences: A059607 A059608 A059609 * A059611 A059612 A059613


KEYWORD

nonn,more


AUTHOR

Andrey V. Kulsha, Feb 02 2001


EXTENSIONS

a(24)a(25) from Max Alekseyev, a(26)a(27) from Paul Underwood, added by Max Alekseyev, Feb 09 2012
a(28)a(29) from Robert Price, Jan 25 2017


STATUS

approved



