GCD of the numbers binomial(3*n, 3*k) for k = 1..n-1.
1, 20, 84, 44, 455, 68, 266, 92, 195, 145, 1364, 4, 9139, 82, 43, 188, 595, 53, 133, 59, 13237, 4, 3082, 284, 13505, 1, 474, 166, 1247, 89, 31, 4, 679, 101, 721, 107, 4033, 113, 1, 1, 27511, 5, 21844, 5764, 335, 274, 6533, 4, 511, 745, 151, 1, 657359, 2, 163, 334
1
See S000733 for the sequence obtained when n is restricted to prime numbers.
T. D. Noe, Plot of 1000 terms
T. D. Noe, Table of 1000 terms
Carl McTague, On the greatest common divisor of binomial(qn,q), binomial(qn,2q),..., binomial(qn,qn-q), arXix 1510.06696 (Oct 22 2015).
(Mma) Join[{1}, Table[GCD @@ Table[Binomial[3*n, 3*k], {k, n - 1}], {n, 2, 100}]]
nonn
T. D. Noe, Oct 27 2015