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A127465 Triangle read by rows: T(n,k) = k*phi(n/k) if k|n, T(n,k)=0 otherwise. 1
1, 1, 2, 2, 0, 3, 2, 2, 0, 4, 4, 0, 0, 0, 5, 2, 4, 3, 0, 0, 6, 6, 0, 0, 0, 0, 0, 7, 4, 4, 0, 4, 0, 0, 0, 8, 6, 0, 6, 0, 0, 0, 0, 0, 9, 4, 8, 0, 0, 5, 0, 0, 0, 0, 10, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 4, 4, 6, 8, 0, 6, 0, 0, 0, 0, 0, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Robert Israel, Table of n, a(n) for n = 1..10011 (rows 1 to 141, flattened)

FORMULA

T(n,k) = k*A054523(n,k).

EXAMPLE

First few rows of the triangle are:

1;

1, 2;

2, 0, 3;

2, 2, 0, 4;

4, 0, 0, 0, 5;

2, 4, 3, 0, 0, 6;

6, 0, 0, 0, 0, 0, 7;

4, 4, 0, 4, 0, 0, 0, 8;

...

MAPLE

A127465 := proc(n, k)

        if n mod k = 0 then

                k*numtheory[phi](n/k) ;

        else

                0;

        end if;

end proc:

seq(seq(A127465(n, m), m=1..n), n=1..12) ; # R. J. Mathar, Nov 08 2011

CROSSREFS

Cf. A054523, A000010 (column k=1), A018804 (row sums).

Sequence in context: A324518 A108807 A129236 * A339033 A327028 A271707

Adjacent sequences:  A127462 A127463 A127464 * A127466 A127467 A127468

KEYWORD

nonn,tabl,easy

AUTHOR

Gary W. Adamson, Jan 15 2007

STATUS

approved

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Last modified August 1 12:37 EDT 2021. Contains 346385 sequences. (Running on oeis4.)