A092394 Largest gcd of two distinct numbers on row n of Pascal's triangle.

1, 1, 2, 5, 5, 7, 28, 42, 42, 165, 132, 429, 1001, 1001, 1430, 6188, 4862, 25194, 41990, 58786, 58786, 245157, 653752, 742900, 1931540, 4345965, 2674440, 17298645, 9694845, 29464725, 94287120, 129644790, 927983760, 811985790, 477638700

Offset: 2

Author

David Wasserman, Mar 21 2004

Keywords

• easy
• nonn

Examples

			For n = 6, the numbers on the row are 1, 6, 15 and 20 and the gcd's of pairs of these are 1, 3, 2 and 5. So a(6) = 5.
		

Links

• Michael De Vlieger, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A007318, A091963.

Programs

Mathematica

Max /@ (GCD[#1, #2] & @@@ Subsets[#, {2}] & /@ Table[Binomial[n, k], {n, 2, 36}, {k, 0, Floor[n/2]}]) (* Michael De Vlieger, Feb 26 2016 *)

PARI

mg(n) = {my(m = 0, v = vecsort(vector(n+1, k, k--; binomial(n,k)),,8));for (k=2, #v, for (j=1, k-1, m = max(m, gcd(v[k], v[j])););); m;} \\ Michel Marcus, Feb 26 2016