A070895 - OEIS

A070895

Triangle read by rows where T(n+1,k)=T(n,k)+n*T(n-1,k) starting with T(n,n)=1 and T(n,k)=0 if n<k.

1, 1, 1, 2, 1, 1, 4, 3, 1, 1, 10, 6, 4, 1, 1, 26, 18, 8, 5, 1, 1, 76, 48, 28, 10, 6, 1, 1, 232, 156, 76, 40, 12, 7, 1, 1, 764, 492, 272, 110, 54, 14, 8, 1, 1, 2620, 1740, 880, 430, 150, 70, 16, 9, 1, 1, 9496, 6168, 3328, 1420, 636, 196, 88, 18, 10, 1, 1, 35696, 23568

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,4

COMMENTS

For n>k+1, T(n,k) is a multiple of k+2.

Eigentriangle of inverse of (-1)^(n-k)*A094587. Row sums are A187044. - Paul Barry, Mar 02 2011

LINKS

Table of n, a(n) for n=0..67.

FORMULA

T(n, k+1)=(T(n, k-1)-T(n-1, k))/k for 0<k<n.

EXAMPLE

Rows start: 1; 1,1; 2,1,1; 4,3,1,1; 10,6,4,1,1; etc.

Triangle begins

1, 1,

2, 1, 1,

4, 3, 1, 1,

10, 6, 4, 1, 1,

26, 18, 8, 5, 1, 1,

76, 48, 28, 10, 6, 1, 1,

232, 156, 76, 40, 12, 7, 1, 1

Production matrix begins

1, 1,

1, 0, 1,

1, 1, 0, 1,

2, 1, 1, 0, 1,

4, 3, 1, 1, 0, 1,

10, 6, 4, 1, 1, 0, 1,

26, 18, 8, 5, 1, 1, 0, 1,

76, 48, 28, 10, 6, 1, 1, 0, 1,

232, 156, 76, 40, 12, 7, 1, 1, 0, 1

Inverse begins

-1, 1,

-1, -1, 1,

0, -2, -1, 1,

0, 0, -3, -1, 1,

0, 0, 0, -4, -1, 1,

0, 0, 0, 0, -5, -1, 1,

0, 0, 0, 0, 0, -6, -1, 1

- Paul Barry, Mar 02 2011

CROSSREFS

Columns include A000085, A000932, A059480. Right hand columns effectively include A000012 (twice), A000027, A005843, A028552. Cf. A062323 for a triangle with similar formulas.

Sequence in context: A091351 A058730 A112705 * A127054 A125790 A370005

Adjacent sequences: A070892 A070893 A070894 * A070896 A070897 A070898

KEYWORD

easy,nonn,tabl

AUTHOR

Henry Bottomley, May 23 2002

STATUS

approved