OFFSET
0,2
COMMENTS
Erdős and Straus asked if a(n) exists for all n.
LINKS
Thomas Bloom, Problem 389.
EXAMPLE
3*4*5*6 ∣ 7*8*9*10, so a(2) = 4.
PROG
(PARI) a(n) = my(k=1); while(prod(i=1, k, n+k+i)%prod(i=1, k, n+i), k++); k;
(Python)
from itertools import count
def A375071(n):
a, b = n+1, n+2
for k in count(1):
if not b%a:
return k
a *= n+k+1
b = b*(n+2*k+1)*(n+2*k+2)//(n+k+1) # Chai Wah Wu, Aug 01 2024
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Ralf Stephan, Jul 29 2024
EXTENSIONS
a(10)-a(18) from Bhavik Mehta, Aug 16 2024
STATUS
approved