A194358 Triangle of divisors of 30^n, each number occurring once.

1, 2, 3, 5, 6, 10, 15, 30, 4, 9, 12, 18, 20, 25, 36, 45, 50, 60, 75, 90, 100, 150, 180, 225, 300, 450, 900, 8, 24, 27, 40, 54, 72, 108, 120, 125, 135, 200, 216, 250, 270, 360, 375, 500, 540, 600, 675, 750, 1000, 1080, 1125, 1350, 1500, 1800, 2250, 2700, 3000

Offset

0,2

Comments

The length of row k is A003215(k), the centered hexagonal numbers, 3k^2 + 3k + 1.

Links

T. D. Noe, Table of n, a(n) for n=0..9260 (rows 0..20)

Example

The triangle has rows beginning with 2^k and ending with 30^k:
1
2, 3, 5, 6, 10, 15, 30
4, 9, 12, 18, 20, 25, 36, 45, 50, 60, 75, 90, 100, 150, 180, 225, 300, 450, 900

Mathematica

Join[{{1}}, Table[Complement[Divisors[30^n], Divisors[30^(n-1)]], {n, 9}]]

Crossrefs

Cf. A194356, A194357.

Cf. A051037 (5-smooth numbers).

Sequence in context: A356605 A018693 A018255 * A018727 A161715 A347799

Adjacent sequences: A194355 A194356 A194357 * A194359 A194360 A194361

Keyword

nonn,tabf

Author

T. D. Noe, Aug 26 2011

Status

approved