OFFSET
1,1
COMMENTS
Equivalently: The image of the function f(x,y)=(x+y)*(x+y+1)/2+y for x,y coprime and 0 < x < y.
LINKS
EXAMPLE
The fully reduced proper fraction 2/5 is mapped to 33 by Cantor's pairing function.
PROG
(Python) # Edited by M. F. Hasler, Mar 25 2023
from math import gcd
def A337308_first(N):
L, b = [], 0
f = lambda a: (a + b) * (a + b + 1) // 2 + b
while N > 0:
b += 1
if len(L) > 1:
L.sort()
while L and L[0] < f(1):
yield L.pop(0)
N -= 1
L.extend(f(a) for a in range(1, b) if gcd(a, b) == 1)
print(list(A337308_first(50)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Alexander Fraebel, Aug 22 2020
STATUS
approved