login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A116999 Numbers n such that 2^n - prime(n)^2 is prime. 0
11, 15, 17, 23, 27, 47, 231, 457, 1249, 1529, 2343, 4693, 5939, 5997, 8367, 19855, 21295 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

No more terms below 30000. - Giovanni Resta (g.resta(AT)iit.cnr.it), Apr 03 2006

EXAMPLE

15 is in the sequence because the 15th prime is 47 and 2^15-47^2=30559 is prime.

MAPLE

a:=proc(n) if isprime(2^n-ithprime(n)^2)=true then n else fi end: seq(a(n), n=1..1600); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 06 2006

PROG

(PARI) for(i=1, 2000, if(isprime(2^i-prime(i)^2), print1(i, ", ")))

CROSSREFS

Sequence in context: A186404 A111322 A069822 * A053675 A031944 A049354

Adjacent sequences:  A116996 A116997 A116998 * A117000 A117001 A117002

KEYWORD

hard,more,nonn

AUTHOR

Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 03 2006

EXTENSIONS

Corrected and extended by Giovanni Resta (g.resta(AT)iit.cnr.it), Apr 03 2006

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 .

Last modified February 15 05:26 EST 2012. Contains 205694 sequences.