A165680 Triangle of the divisors of the coefficients of triangles A138771 and A165675

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 6, 1, 1, 1, 2, 6, 24, 1, 1, 1, 2, 6, 24, 120, 1, 1, 1, 2, 6, 24, 120, 720, 1, 1, 1, 2, 6, 24, 120, 720, 5040, 1, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 1, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880

Offset

1,10

Links

Table of n, a(n) for n=1..66.

Formula

a(n) = A138771(n)/A165675(n-1).

Example

Triangle starts:
1,
1, 1,
1, 1, 1,
1, 1, 1, 2,
1, 1, 1, 2, 6,
1, 1, 1, 2, 6, 24,
1, 1, 1, 2, 6, 24, 120,
1, 1, 1, 2, 6, 24, 120, 720,
1, 1, 1, 2, 6, 24, 120, 720, 5040,
1, 1, 1, 2, 6, 24, 120, 720, 5040, 40320,
1, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880,
...

Maple

nmax:=11: for n from 1 to nmax do a(n, 1):=1 od: for n from 2 to nmax do for m from 2 to n do a(n, m):=(m-2)! od: od: for n from 1 to nmax do seq(a(n, m), m=1..n) od;

Crossrefs

Cf. A138771, A165675 and A000142.

A000012 (3x), A007395, A010722, A010863 equal the first six left hand columns.

A159333 equals, for n=>-1, all right hand columns.

A067078 equals the row sums.

Sequence in context: A126886 A179272 A264753 * A248049 A231867 A105685

Adjacent sequences: A165677 A165678 A165679 * A165681 A165682 A165683

Keyword

easy,nonn,tabl

Author

Johannes W. Meijer, Oct 05 2009

Status

approved