OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10585; the first 145 rows of triangle
EXAMPLE
The first twelve rows of the triangle:
1,
5, 2,
13, 16, 4,
25, 67, 12, 7,
41, 191, 106, 46, 11,
61, 436, 80, 31, 23, 16,
85, 862, 596, 379, 211, 92, 22,
113, 1541, 302, 781, 59, 277, 38, 29,
145, 2557, 1954, 193, 991, 631, 58, 154, 37,
181, 4006, 822, 2416, 467, 96, 212, 436, 57, 46,
221, 5996, 4852, 3829, 2927, 2146, 1486, 947, 529, 232, 56,
265, 8647, 1832, 706, 355, 3487, 142, 1771, 109, 94, 80, 67
PROG
(Python)
from sympy import lcm, gcd
def t(n, k): return (2 + ((gcd(n, k) + lcm(n, k))**2) - gcd(n, k) - 3*lcm(n, k))/2
for n in range(1, 21): print [t(n, k) for k in range(1, n + 1)][::-1] # Indranil Ghosh, May 11 2017
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, May 06 2017
STATUS
approved