A113926 Triangle where a(1,1)=1. a(n,m) = GCD of m and sum of terms in row (n-1).

1, 1, 1, 1, 2, 1, 1, 2, 1, 4, 1, 2, 1, 4, 1, 1, 1, 3, 1, 1, 3, 1, 2, 1, 2, 5, 2, 1, 1, 2, 1, 2, 1, 2, 7, 2, 1, 2, 3, 2, 1, 6, 1, 2, 9, 1, 1, 3, 1, 1, 3, 1, 1, 9, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 11, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 2, 1, 6, 1, 2, 9, 2, 1, 6, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,5

Comments

The sum of the terms in the n-th row is A100675(n+1).

Links

Table of n, a(n) for n=1..105.

Example

Row 6 is[1,1,3,1,1,3], which has a sum of 10.
So row 7 is [GCD(1,10),GCD(2,10),GCD(3,10),GCD(4,10),GCD(5,10),GCD(6,10),GCD(7,10)]
= [1,2,1,2,5,2,1].

Maple

T[1, 1]:=1: for n from 1 to 15 do for k from 1 to n do T[n, k]:=gcd(k, add(T[n-1, j], j=1..n-1)) od: od: for n from 1 to 15 do seq(T[n, k], k=1..n) od; # yields sequence in triangular form - Emeric Deutsch, Feb 13 2006

Crossrefs

Cf. A100675.

Sequence in context: A304080 A137843 A130194 * A276376 A165585 A082506

Adjacent sequences: A113923 A113924 A113925 * A113927 A113928 A113929

Keyword

nonn,tabl

Author

Leroy Quet, Jan 30 2006

Extensions

More terms from Emeric Deutsch, Feb 13 2006

Status

approved