A127449 Triangle T(n,k) = n if gcd(n,k)=1, =0 otherwise.

1, 2, 0, 3, 3, 0, 4, 0, 4, 0, 5, 5, 5, 5, 0, 6, 0, 0, 0, 6, 0, 7, 7, 7, 7, 7, 7, 0, 8, 0, 8, 0, 8, 0, 8, 0, 9, 9, 0, 9, 9, 0, 9, 9, 0, 10, 0, 10, 0, 0, 0, 10, 0, 10, 0

Offset

1,2

Links

Table of n, a(n) for n=1..55.

Formula

T(n,k) = n *A054521(n,k), 1<=k<=n.

Example

First few rows of the triangle are:
1;
2, 0;
3, 3, 0;
4, 0, 4, 0;
5, 5, 5, 5, 0;
6, 0, 0, 0, 6, 0;
7, 7, 7, 7, 7, 7, 0;
...

Mathematica

Table[If[GCD[n, k]==1, n, 0], {n, 10}, {k, n}]//Flatten (* Harvey P. Dale, Aug 12 2021 *)

Crossrefs

Cf. A002618 (row sums), A054521.

Sequence in context: A088276 A099838 A369280 * A328911 A138057 A053727

Adjacent sequences: A127446 A127447 A127448 * A127450 A127451 A127452

Keyword

nonn,tabl,easy

Author

Gary W. Adamson, Jan 14 2007

Status

approved