OFFSET
1,1
COMMENTS
One less than the associated value in A047845. - R. J. Mathar, Jan 05 2011
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Marc Wolf, François Wolf, Representation theorem of composite odd numbers indices, SCIREA Journal of Mathematics (2018) 3.3, 106-117.
FORMULA
a(n) ~ n. - Charles R Greathouse IV, Dec 28 2011
MATHEMATICA
lst={}; Do[If[ !PrimeQ[2*n+3], AppendTo[lst, n]], {n, 6!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 10 2009 *)
Select[Range[120], CompositeQ[2 # + 3] &] (* Michael De Vlieger, Oct 17 2018 *)
PROG
(PARI) for(n=1, 115, if(!isprime(2*n+3), print1(n, ", "))) \\ Joerg Arndt, Dec 19 2010
(Magma) [ n: n in [0..120] | not IsPrime(2*n+3) ]; // Klaus Brockhaus, Dec 19 2010
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 21 2008
EXTENSIONS
Edited by Ray Chandler, Jan 07 2009
STATUS
approved