A165936 A sequence of triples of squarefree consecutive integers each composed of exactly three primes.

1309, 1310, 1311, 1885, 1886, 1887, 2013, 2014, 2015, 2665, 2666, 2667, 3729, 3730, 3731, 5133, 5134, 5135, 6061, 6062, 6063, 6213, 6214, 6215, 6305, 6306, 6307, 6477, 6478, 6479, 6853, 6854, 6855, 6985, 6986, 6987, 7257, 7258, 7259, 7953, 7954, 7955, 8393

Offset: 1

Author

Richard L. Peterson (rl_pete(AT)yahoo.com), Oct 01 2009

Keywords

• nonn

Examples

			1309 = 7 * 11 * 17, 1310 = 2 * 5 * 131, 1311 = 3 * 19 * 23.
		

Programs

Magma

a:=[]; f:=func; for k in [2..8500] do  if f(k) then a:=a cat [k, k+1, k+2]; end if;  end for; a; // Marius A. Burtea, Oct 05 2019

Mathematica

Select[Partition[Range[10000],3,1],AllTrue[#,SquareFreeQ]&&Union[ PrimeOmega[ #]] == {3}&]//Flatten (* Harvey P. Dale, Oct 02 2017 *)

Formula

a(3n+1) = A066509(n+1); a(3n+2) = 1 + a(3n+1); a(3n+3) = 1 + a(3n+2). - R. J. Mathar, Nov 27 2011

Extensions

More terms from Harvey P. Dale, Oct 02 2017