OFFSET
1,2
COMMENTS
In other words a(n) is least k such that (k, a(n-2)) = 1 and rad(a(n-2)*a(n-1)*k) is a primorial number (alternatively i*j*k is in A055932).
Conjectures: A permutation of the positive integers, a(n) = prime p (> 2) iff p is least unused odd term, 2|i, and rad(i*j) is a primorial number divisible by all primes < p but not by p; primes appear in natural order.
LINKS
Dominic McCarty, Table of n, a(n) for n = 1..10000
Dominic McCarty, Java program for A374351
EXAMPLE
a(1,2,3) = 1,2,3 the lexicographically earliest triple of numbers satisfying the definition: 3 and 1 are coprime whilst 1*2*3 = 6 = A002110(2).
a(4) = 5 because (2,5) = 1 and 2*3*5 = 30 = A002110(3).
a(9,10,11) = 8,12,15 and 7 is the smallest novel number prime to 12 and rad(12*15*7) = 210 = A002110(4).
PROG
(Java) See Dominic McCarty link.
CROSSREFS
KEYWORD
nonn
AUTHOR
David James Sycamore, Jul 09 2024
EXTENSIONS
More terms from Dominic McCarty, Aug 19 2024
STATUS
approved