OFFSET
1,2
COMMENTS
2*A155724(m,n) + 9 = (2n+1)*(2m+1) are not prime and create entries of this form. Also, one less than the associate entry in A153053, two less than the associated A153052. - R. J. Mathar, Jan 05 2011
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
EXAMPLE
Distribution of the terms in the following triangular array:
0;
3, 8;
6, 13, 20;
9, 18, 27, 36;
12, 23, 34, 45, 56;
15, 28, 41, 54, 67, 80;
18, 33, 48, 63, 78, 93, 108;
21, 38, 55, 72, 89, 106, 123, 140;
24, 43, 62, 81, 100, 119, 138, 157, 176;
27, 48, 69, 90, 111, 132, 153, 174, 195, 216;
30, 53, 76, 99, 122, 145, 168, 191, 214, 237, 260;
33, 58, 83, 108, 133, 158, 183, 208, 233, 258, 283, 308;
36, 63, 90, 117, 144, 171, 198, 225, 252, 279, 306, 333, 360;
etc.
the values of (2*h*k + k + h - 4) with h >= k >= 1. - Vincenzo Librandi, Jan 16 2013
MATHEMATICA
Select[Range[0, 80], !PrimeQ[2*#+9]&] (* Vincenzo Librandi, Mar 01 2012 *)
PROG
(Magma) [n: n in [0..115]| not IsPrime(2*n+9)]; // Vincenzo Librandi, Mar 01 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jan 25 2009
STATUS
approved