OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
*;
2, *;
*, 7, *;
5, *, 14, *;
*, 12, *, 23, *;
8, *, 21, *, 34, *;
*, 17, *, 32, *, 47, *; etc.
where * marks the non-integer values of (2*n*k + k + n - 3)/2 with n >= k >= 1. - Vincenzo Librandi, Nov 21 2012
MATHEMATICA
Select[Range[200], !PrimeQ[4# + 7] &] (* Vincenzo Librandi, Nov 21 2012 *)
PROG
(Magma) [n: n in [1..120] | not IsPrime(4*n + 7)]; // Vincenzo Librandi, Nov 21 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 18 2008
STATUS
approved