A182720 - OEIS

A182720

Triangle read by rows: T(n,k) = A000041(k) if k divides n, T(n,k)=0 otherwise.

1, 1, 2, 1, 0, 3, 1, 2, 0, 5, 1, 0, 0, 0, 7, 1, 2, 3, 0, 0, 11, 1, 0, 0, 0, 0, 0, 15, 1, 2, 0, 5, 0, 0, 0, 22, 1, 0, 3, 0, 0, 0, 0, 0, 30, 1, 2, 0, 0, 7, 0, 0, 0, 0, 42, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 56, 1, 2, 3, 5, 0, 11, 0, 0, 0, 0, 0, 77, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 101, 1, 2, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 135, 1, 0, 3, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 176

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..120.

FORMULA

T(n,k) = A051731(n,k)*A000041(k).

EXAMPLE

1, 2,

1, 0, 3,

1, 2, 0, 5,

1, 0, 0, 0, 7,

1, 2, 3, 0, 0, 11,

1, 0, 0, 0, 0, 0, 15,

1, 2, 0, 5, 0, 0, 0, 22,

1, 0, 3, 0, 0, 0, 0, 0, 30,

1, 2, 0, 0, 7, 0, 0, 0, 0, 42

MAPLE

A182720 := proc(n, k) if n mod k = 0 then combinat[numbpart](k); else 0; end if ; end proc:

seq(seq(A182720(n, k), k=1..n), n=1..15) ;

CROSSREFS

Cf. A000005, A000041, A051731, A168016, A168017, A168018, A168021. Positive integers of row n give A168017.

Row sums give A047968.

Sequence in context: A141543 A333432 A333500 * A347316 A146540 A162922

Adjacent sequences: A182717 A182718 A182719 * A182721 A182722 A182723

KEYWORD

nonn,easy,tabl

AUTHOR

Omar E. Pol, Nov 28 2010

STATUS

approved