A335572 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The last term of row n is n+1.

LINKS

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

EXAMPLE

Triangle begins:

[2]

[3]

[4]

[4, 5]

[6]

[5, 7]

[8]

[6, 9]

[6, 10]

[7, 11]

...

MATHEMATICA

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

PROG

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

CROSSREFS

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

Sequence in context: A147847 A370386 A375626 * A268680 A126974 A354459

Adjacent sequences: A335569 A335570 A335571 * A335573 A335574 A335575

KEYWORD

nonn,tabf

AUTHOR

Michel Marcus, Jan 26 2021

STATUS

approved