OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(1)=2 because 2*2-3=1 (nonprime) and 2*2+3=7 (prime);
a(2)=29 because 2*29-3=55 (nonprime) and 2*29+3=61 (prime).
MAPLE
a := proc (n): if isprime(n) = true and isprime(2*n-3) = true and isprime(2*n+3) = false then n elif isprime(n) = true and isprime(2*n-3) = false and isprime(2*n+3) = true then n else end if end proc: seq(a(n), n = 1 .. 700); # Emeric Deutsch, Feb 15 2010
MATHEMATICA
Select[Prime[Range[100]], Total[Boole[PrimeQ[2#+{3, -3}]]]==1&] (* Harvey P. Dale, Mar 27 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jan 30 2010
EXTENSIONS
Definition edited by Emeric Deutsch, Feb 15 2010
Corrected and extended by Emeric Deutsch, Feb 15 2010
STATUS
approved