A143267 Triangle read by rows, A130207 * A000012 * A127648.

1, 1, 2, 2, 4, 6, 2, 4, 6, 8, 4, 8, 12, 16, 20, 2, 4, 6, 8, 10, 12, 6, 12, 18, 24, 30, 36, 42, 4, 8, 12, 16, 20, 24, 28, 32, 6, 12, 18, 24, 30, 36, 42, 48, 54, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100

Offset

1,3

Comments

Left border = phi(n), A000010.

Row sums = A143268, phi(n)*T(n): (1, 3, 12, 20, 60, 42,...)

Links

Table of n, a(n) for n=1..65.

Formula

Triangle read by rows, A130207 * A000012 * A127648; 1<=k<=n. T(n,k) = phi(n)*k.

Example

First few rows of the triangle =
1;
1, 2;
2, 4, 6;
2, 4, 6, 8;
4, 8, 12, 16, 20;
2, 4, 6, 8, 10, 12;
6, 12, 18, 24, 30, 36, 42;
4, 8, 12, 16, 20, 24, 28, 32;
...
Row 5 = (4, 8, 12, 16, 20) since the first terms of phi(5) = 4; so we perform (4*1, 4*2, 4*3, 4*4, 4*5).

Crossrefs

Cf. A130207, A127648, A000010.

Sequence in context: A087377 A010768 A373208 * A113463 A278217 A191674

Adjacent sequences: A143264 A143265 A143266 * A143268 A143269 A143270

Keyword

nonn,tabl

Author

Gary W. Adamson, Aug 03 2008

Status

approved