A159905 - OEIS

A159905

Triangle read by rows, Mobius transform of A004736

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

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OFFSET

1,4

COMMENTS

Row sums = A007438, Mobius transform of the triangular numbers.

Left border = phi(n), A000010.

LINKS

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

FORMULA

Triangle read by rows, A054525 * A004736. A054525 = the Mobius transform, A004736 = the natural number "decrescendo" triangle: (1; 2,1; 3,2,1;...)

EXAMPLE

First few rows of the triangle =

1, 1;

2, 2, 1;

2, 2, 2, 1;

4, 4, 3, 2, 1;

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

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

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

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

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

...

CROSSREFS

Cf. A007438

Sequence in context: A168258 A116204 A291592 * A283735 A274534 A224030

Adjacent sequences: A159902 A159903 A159904 * A159906 A159907 A159908

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Apr 25 2009

STATUS

approved