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!)
 A152908 Primes p=prime(k) such that p - nonprime(k) is prime and p + nonprime(k) is not prime, where prime(n) is the n-th prime and nonprime(n) is the n-th nonprime starting with nonprime(1) = 0. 1
 3, 17, 37, 53, 71, 79, 113, 127, 151, 167, 277, 317, 383, 397, 419, 421, 509, 577, 599, 641, 643, 653, 683, 761, 797, 829, 877, 937, 1049, 1051, 1087, 1097, 1163, 1249, 1283, 1297, 1367, 1439, 1483, 1607, 1699, 1913, 1933, 1993, 2017, 2081, 2089, 2129, 2131 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE 3(2) - 1(2) = 2 (prime) and 3(2) + 1(2) = 4 (nonprime), so 3 is in the sequence. 17(7) - 10(7) = 7 (prime) and 17(7) + 10(7) = 27 (nonprime), so 17 is in the sequence. 37(12) - 18(12) = 19 (prime) and 37(12) + 18(12) = 55 (nonprime), so 37 is in the sequence. 53(16) - 24(16) = 29(prime) and 53(16) + 24(16) = 77 (nonprime), so 53 is in the sequence. 71(20) - 28(20) = 43(prime) and 71(20) + 28(20) = 99 (nonprime), so 71 is in the sequence. MAPLE A141468 := proc(n) option remember ; local a; if n = 1 then 0 ; else for a from procname(n-1)+1 do if not isprime(a) then RETURN(a) ; fi; od; fi; end: for n from 1 to 700 do p := ithprime(n) ; if isprime( p- A141468(n)) and not isprime(p+A141468(n)) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Jan 17 2009 CROSSREFS Cf. A000040, A141468, A144517. Sequence in context: A297735 A266062 A031290 * A031386 A146813 A106895 Adjacent sequences:  A152905 A152906 A152907 * A152909 A152910 A152911 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Dec 15 2008 EXTENSIONS 227, 619, 1039, etc. removed, and 797, 1087, etc. added, by R. J. Mathar, Jan 17 2009 Better definition from Michel Marcus, Aug 07 2017 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 August 3 01:36 EDT 2021. Contains 346429 sequences. (Running on oeis4.)