A129822 Array read by rows: each row lists three consecutive nonprime odd numbers.

91, 93, 95, 115, 117, 119, 117, 119, 121, 119, 121, 123, 121, 123, 125, 141, 143, 145, 143, 145, 147, 183, 185, 187, 185, 187, 189, 201, 203, 205, 203, 205, 207, 205, 207, 209, 213, 215, 217, 215, 217, 219, 217, 219, 221, 243, 245, 247, 245, 247, 249, 285

Offset: 1

Author

Roger L. Bagula, May 20 2007

Keywords

• nonn
• tabf

Links

• Robert Israel, Table of n, a(n) for n = 1..10002

Crossrefs

Cf. A099019 (second column), A161945 (first column).

Programs

Maple

a:=proc(n) if isprime(2*n-1)=false and isprime(2*n+1)=false and isprime(2*n+3)=false then 2*n-1, 2*n+1, 2*n+3 else fi end: seq(a(n),n=1..150);

Mathematica

Flatten[Table[If[OddQ[n - 1] && PrimeQ[n - 1] == False && PrimeQ[n + 1] == False && PrimeQ[n + 3] == False, {{n - 1}, {n + 1}, {n + 3}}, {}], {n, 2, 300}]]
Select[Partition[Range[1,301,2],3,1],NoneTrue[#,PrimeQ]&]//Flatten (* Harvey P. Dale, Jul 16 2021 *)

Extensions

Edited by N. J. A. Sloane, Jun 09 2007

Definition modified by Harvey P. Dale, Jul 16 2021