A125728 -id:A125728 - cp's OEIS frontend

A144379 Triangle read by rows, first n terms of an array formed by A054521 * A054521(transform).

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 4, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 4, 2, 6, 1, 1, 1, 2, 2, 2, 3, 4, 1, 1, 2, 1, 3, 2, 4, 3, 6, 1, 1, 1, 2, 2, 1, 2, 3, 2, 4, 1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10, 1, 1, 1, 1, 1, 2, 2, 3, 3, 2, 3, 4, 1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10, 4, 12, 1, 1, 1, 2, 2, 2, 3, 3, 2, 3, 4, 3, 5

Offset: 1

Gary W. Adamson, Sep 19 2008

Right border = phi(n): (1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10,...).

Row sums = A125728: (1, 2, 4, 5, 10, 7, 18, 16, 23,...) = the number of positive integers less <=k coprime to both k and n.

			A054521 * A054521(transform) =
1, 1, 1, 1, 1, 1, 1,...
1, 1, 1, 1, 1, 1, 1,...
1, 1, 2, 1, 2, 1, 2,...
1, 1, 1, 2, 2, 1, 2,...
1, 1, 2, 2, 4, 1, 4,...
...
Then extract the lower half of the array including the diagonal, A000010, phi(n); getting triangle A144379:
1;
1, 1;
1, 1, 2
1, 1, 1, 2;
1, 1, 2, 2, 4;
1, 1, 1, 1, 1, 2;
1, 1, 2, 2, 4, 2, 6;
1, 1, 1, 2, 2, 2, 3, 4;
1, 1, 2, 1, 3, 2, 4, 3, 6;
1, 1, 1, 2, 2, 1, 2, 3, 2, 4;
1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10;
...

A054521, Cf. A000010, A125728

Given A054521 as an infinite lower triangular matrix, perform A054521(transform). Multiply the result by A054521 getting an array, then extract the first n terms of each row to form a new triangle.

cp's OEIS Frontend

A144379 Triangle read by rows, first n terms of an array formed by A054521 * A054521(transform).

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