A335572 Irregular triangle whose row n is the set of numbers d+n/d where d is a divisor of n.

2, 3, 4, 4, 5, 6, 5, 7, 8, 6, 9, 6, 10, 7, 11, 12, 7, 8, 13, 14, 9, 15, 8, 16, 8, 10, 17, 18, 9, 11, 19, 20, 9, 12, 21, 10, 22, 13, 23, 24, 10, 11, 14, 25, 10, 26, 15, 27, 12, 28, 11, 16, 29, 30, 11, 13, 17, 31, 32, 12, 18, 33, 14, 34, 19, 35, 12, 36, 12, 13, 15, 20, 37

Offset: 1

Author

Michel Marcus, Jan 26 2021

Keywords

• nonn
• tabf

Comments

The last term of row n is n+1.

Examples

			Triangle begins:
  [2]
  [3]
  [4]
  [4, 5]
  [6]
  [5, 7]
  [8]
  [6, 9]
  [6, 10]
  [7, 11]
  ...
		

Links

• Michel Marcus, Rows n=1..4000 of triangle, flattened

Crossrefs

Cf. A027750 (divisors of n), A038548 (row lengths), A063655 (1st column).

Programs

Mathematica

Table[Map[# + n/# &, #[[-Ceiling[Length[#]/2] ;; -1 ]] ] &@ Divisors[n], {n, 36}] // Flatten (* Michael De Vlieger, Jan 27 2021 *)

PARI

row(n) = my(d=divisors(n)); Set(vector(#d,k,d[k]+n/d[k]));