OFFSET
1,1
FORMULA
T(m, a) = denominator(R(m, a)) with the rational triangle R(m, a) = (m^4 - 30*m^2*a^2 + 60*m*a^3 - 30*a^4)/(120*m), m >= 1, a = 1, ..., m.
EXAMPLE
The triangle T(m, a) begins:
m\a 1 2 3 4 5 6 7 8 9 10 ...
1: 120
2: 120 15
3: 120 120 40
4: 240 15 240 15
5: 120 120 120 120 24
6: 120 15 40 15 120 5
7: 840 840 840 840 840 840 120
8: 480 30 480 15 480 30 480 15
9: 360 360 40 360 360 40 360 360 40
10: 120 15 120 15 24 15 120 15 120 3
... For the triangle of the rationals R(m, a) see A268919.
MATHEMATICA
Flatten[Table[(m^4-30m^2 a^2+60m a^3-30a^4)/(120m), {m, 12}, {a, m}]]// Denominator (* Harvey P. Dale, Mar 03 2020 *)
CROSSREFS
KEYWORD
AUTHOR
Wolfdieter Lang, Feb 25 2016
STATUS
approved