A156837 Triangle read by rows, A051731 * A156348

1, 2, 1, 2, 0, 1, 3, 3, 0, 1, 2, 0, 0, 0, 1, 4, 4, 4, 0, 0, 1, 2, 0, 0, 0, 0, 0, 1, 4, 7, 0, 5, 0, 0, 0, 1, 3, 0, 7, 0, 0, 0, 0, 0, 1, 4, 6, 0, 0, 6, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 12, 14, 11, 0, 7, 0, 0, 0, 0, 0, 1

Offset

1,2

Comments

Left border: A000005(n).

Row sums = 3 iff n-th row is prime.

Links

Table of n, a(n) for n=1..78.

Formula

Triangle read by rows, A051731 * A156348 = inverse Mobius transform of A156348

Example

First few rows of the triangle =
1;
2, 1;
2, 0, 1;
3, 3, 0, 1;
2, 0, 0, 0, 1;
4, 4, 4, 0, 0, 1;
2, 0, 0, 0, 0, 0, 1;
4, 7, 0, 5, 0, 0, 0, 1;
3, 0, 7, 0, 0, 0, 0, 0, 1;
4, 6, 0, 0, 6, 0, 0, 0, 0, 1;
2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
6, 12, 14, 11, 0, 7, 0, 0, 0, 0, 0, 1;
2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
4, 8, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 1;
...

Maple

A156837 := proc(n, k)
    add(A051731(n, j)*A156348(j, k), j=k..n) ;
end proc: # R. J. Mathar, Mar 03 2013

Crossrefs

Cf. A156348, A051731, A000005, A156838 (row sums).

Sequence in context: A127170 A143335 A099505 * A255935 A374394 A129559

Adjacent sequences: A156834 A156835 A156836 * A156838 A156839 A156840

Keyword

nonn,tabl,easy

Author

Gary W. Adamson & Mats Granvik, Feb 16 2009

Status

approved