A161945 Numbers n with property that three consecutive odd numbers {n,n+2,n+4} are all composite.

91, 115, 117, 119, 121, 141, 143, 183, 185, 201, 203, 205, 213, 215, 217, 243, 245, 285, 287, 295, 297, 299, 301, 319, 321, 323, 325, 339, 341, 361, 391, 403, 411, 413, 423, 425, 451, 469, 471, 473, 481, 493, 511, 513, 515, 525, 527, 529, 531, 533, 535, 549

Offset: 1

Author

Zak Seidov, Jun 22 2009

Keywords

• nonn

Examples

			143 is in the sequence because 143=11*13, 145=5*29, 147=3*49. [_Emeric Deutsch_, Jun 27 2009]
		

Programs

Maple

a:= proc(n) if not (isprime(2*n-1) or isprime(2*n+1) or isprime(2*n+3)) then 2*n-1 end if end proc: seq(a(n), n = 2 .. 300); # Emeric Deutsch, Jun 27 2009

Mathematica

fQ[n_]:=!PrimeQ[n]&&!PrimeQ[n+2]&&!PrimeQ[n+4];Select[Range[3,1000,2],fQ] (* Vladimir Joseph Stephan Orlovsky, Apr 16 2011 *)