login
A153235
Numbers n such that 8*n+7 is not prime.
1
1, 4, 6, 7, 10, 11, 13, 14, 16, 17, 19, 21, 22, 25, 26, 28, 30, 31, 34, 35, 36, 37, 39, 40, 41, 42, 43, 46, 48, 49, 50, 51, 52, 55, 56, 58, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 76, 77, 79, 81, 82, 83, 84, 85, 86, 87, 88, 91, 94, 95, 96, 97, 98, 99, 100, 101
OFFSET
1,2
LINKS
EXAMPLE
Distribution of the terms in the following triangular array:
*;
1,*;
*,*,*;
*,*,7,*;
*,6,*,*,*;
4,*,*,*,17,*;
*,*,*,16,*,*,*;
*,*,14,*,*,*,31,*;
*,11,*,*,*,30,*,*,*;
7,*,*,*,28,*,*,*,49,*:
*,*,*,25,*,*,*,48,*,*,*;
*,*,21,*,*,*,46,*,*,*,71,*; etc.
where * marks the non-integer values of (2*h*k + k + h - 3)/4 with h >= k >= 1. - Vincenzo Librandi, Jan 15 2013
MATHEMATICA
Select[Range[0, 200], !PrimeQ[8 # + 7] &] (* Vincenzo Librandi, Jan 12 2013 *)
PROG
(Magma) [n: n in [0..110] | not IsPrime(8*n+7)]; // Vincenzo Librandi, Jan 12 2013
CROSSREFS
Cf. A139487.
Sequence in context: A123088 A256657 A189085 * A286491 A133483 A153082
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 21 2008
STATUS
approved