This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A169647 Primes p such that (p-2)/3 is not a prime number. 4
 2, 3, 5, 7, 13, 19, 29, 31, 37, 43, 47, 61, 67, 73, 79, 83, 97, 101, 103, 107, 109, 127, 137, 139, 149, 151, 157, 163, 167, 173, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 241, 257, 263, 271, 277, 281, 283, 307, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The old definition was "Start with the list of primes; accept 2 but remove the list of primes S(2), defined in the comments; accept the next prime (3) but remove the list of primes S(3); repeat". If p is a prime, S(p) denotes the list of primes {3p+2, 3(3p+2)+2, 3(3(3p+2)+2)+2, ...}, stopping as soon as we reach the first composite number. Thus S(2) = {}, S(3) = {11}, S(5) = {17, 53}, S(7) = {23, 71}, etc. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Prime[Range[80]], !PrimeQ[(#-2)/3]&] (* Harvey P. Dale, Mar 08 2012 *) CROSSREFS Sequence in context: A062252 A153800 A147791 * A072467 A062326 A198273 Adjacent sequences:  A169644 A169645 A169646 * A169648 A169649 A169650 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Apr 05 2010, based on an email message from Vincenzo Librandi. EXTENSIONS Checked by Dan Drake, Jun 17 2010 New definition from Jon E. Schoenfield, Jun 18 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 25 16:04 EDT 2019. Contains 322461 sequences. (Running on oeis4.)