OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
MATHEMATICA
fQ[n_] := fQ[n_] := IntegerQ[ Binomial[2n, n]/(n(n + 1)/3)] && !IntegerQ[ Binomial[2n, n]/n]; Select[ Range@4463, fQ@# &]
PROG
(Python)
A120623_list, b = [], 1
for n in range(1, 10**5):
if b % n and not (3*b) % n:
A120623_list.append(n)
b = b*(4*n+2)//(n+2) # Chai Wah Wu, Mar 30 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jun 19 2006
EXTENSIONS
Better description from Joel B. Lewis, Nov 15 2006
STATUS
approved