1,6

Row sums = A057661: (1, 2, 4, 6, 11, 11, 22,...). Right border = A000010, phi(n).

Triangle read by rows, A051731 * A054533 * A000012. A051731 = the inverse Mobius transform. A054533 = the lower left half of the Ramanujan sum table. The operation (* A000012) takes partial sums of (A051731 * A054533) starting from the right.

First few rows of the triangle =

1;

1, 1;

1, 1, 2;

1, 1, 2, 2;

1, 1, 2, 3, 4;

1, 1, 2, 2, 3, 2;

1, 1, 2, 3, 4, 5, 6;

1, 1, 2, 2, 4, 4, 4, 4;

1, 1, 2, 3, 3, 3, 6, 6, 6;

1, 1, 2, 2, 4, 4, 5, 4, 5, 4;

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

1, 1, 2, 2, 3, 2, 4, 4, 6, 6, 4, 4;

1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12;

1, 1, 2, 2, 4, 4, 6, 6, 7, 6, 7, 6, 7, 6;

1, 1, 2, 3, 3, 3, 5, 4, 3, 5, 9, 8, 10, 9, 8;

1, 1, 2, 2, 4, 4, 4, 4, 8, 8, 8, 8, 8, 8, 8, 8;

...

Cf. A051731, A054533, A057661

Sequence in context: A087062 A110537 A144434 this_sequence A144464 A138015 A103444

Adjacent sequences: A159933 A159934 A159935 this_sequence A159937 A159938 A159939

nonn,tabl

Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 26 2009