A194359 Triangle of divisors of 210^n, each number occurring once.

1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210, 4, 9, 12, 18, 20, 25, 28, 36, 45, 49, 50, 60, 63, 75, 84, 90, 98, 100, 126, 140, 147, 150, 175, 180, 196, 225, 245, 252, 294, 300, 315, 350, 420, 441, 450, 490, 525, 588, 630, 700, 735, 882, 900

Offset: 0

Author

T. D. Noe, Aug 26 2011

Keywords

• nonn
• tabf

Comments

The length of row k is A005917, the rhombic dodecahedral numbers, (k+1)^4 - k^4. The triangle has rows beginning with 2^k and ending with 210^k.

Links

• T. D. Noe, Rows n = 0..9

Crossrefs

Cf. A018336, A194356, A194357, A194358.

Programs

Mathematica

Join[{{1}}, Table[Complement[Divisors[210^n], Divisors[210^(n-1)]], {n, 9}]]
Take[DeleteDuplicates[Flatten[Divisors/@(210^Range[5])]],100] (* Harvey P. Dale, Sep 03 2020 *)