The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A120450 Number of ways to express a prime p as 2*p1 + 3*p2, where p1, p2 are primes or 1. 1
 0, 0, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 4, 3, 3, 3, 5, 4, 4, 4, 4, 4, 4, 6, 3, 5, 4, 4, 4, 6, 5, 5, 5, 5, 7, 5, 6, 6, 6, 6, 7, 5, 6, 7, 6, 7, 9, 8, 8, 6, 7, 7, 8, 7, 9, 6, 10 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS It seems that every prime p > 3 can be expressed as 2*p1 + 3*p2, where p1, p2 are primes or 1. I have tested it for the first 1500 primes (up to 12553) and it is true. LINKS EXAMPLE a(11)=2 because we can write 31 (the 11th prime) as 2* 5 + 3* 7 OR 2* 11 + 3* 3 a(12)=3 because we can write 37 (the 12th prime) as 2* 2 + 3* 11 OR 2* 11 + 3* 5 OR 2* 17 + 3* 1 CROSSREFS Sequence in context: A030603 A092670 A210528 * A127238 A072114 A090621 Adjacent sequences:  A120447 A120448 A120449 * A120451 A120452 A120453 KEYWORD nonn AUTHOR Vassilis Papadimitriou, Jul 20 2006 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 September 29 18:27 EDT 2020. Contains 337432 sequences. (Running on oeis4.)