A109709 Triangle in which n-th row gives the prime factors of the n-th composite number with repetition.

2, 2, 2, 3, 2, 2, 2, 3, 3, 2, 5, 2, 2, 3, 2, 7, 3, 5, 2, 2, 2, 2, 2, 3, 3, 2, 2, 5, 3, 7, 2, 11, 2, 2, 2, 3, 5, 5, 2, 13, 3, 3, 3, 2, 2, 7, 2, 3, 5, 2, 2, 2, 2, 2, 3, 11, 2, 17, 5, 7, 2, 2, 3, 3, 2, 19, 3, 13, 2, 2, 2, 5, 2, 3, 7, 2, 2, 11, 3, 3, 5, 2, 23, 2, 2, 2, 2, 3, 7, 7, 2, 5, 5, 3, 17, 2, 2, 13, 2, 3, 3, 3

Offset: 1

Author

Lior Manor, Aug 08 2005

Keywords

• nonn
• tabf

Examples

			Irregular triangle begins:
  2, 2;
  2, 3;
  2, 2, 2;
  3, 3;
  2, 5;
  ...
		

Crossrefs

Column k=1 gives A056608.

Last terms in rows give A052369.

Row lengths give A062502(n+1).

Cf. A002808, A027746.

Programs

Mathematica

fn[{a_,b_}]:=Table[a,b];Flatten[Table[fn/@FactorInteger[ ResourceFunction["Composite"][n]],{n,37}]] (* James C. McMahon, Mar 29 2024 *)