This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A059610 Numbers n such that 2^n-9 is prime. 13
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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. LINKS Search for 2^n-9, PRP Top Records EXAMPLE 243 is in the sequence because 2^243-9 is prime. MATHEMATICA Select[Range[3, 20000], PrimeQ[2^#-9]&] (*From Vladimir Joseph Stephan Orlovsky, Feb 26 2011*) CROSSREFS 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 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 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .