

A130296


Triangle read by rows: T[i,1]=i, T[i,j]=1 for 1 < j <= i = 1,2,3,...


20



1, 2, 1, 3, 1, 1, 4, 1, 1, 1, 5, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 8, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 14, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
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OFFSET

1,2


COMMENTS

This sequence was formerly named "reversals of A051340", but it is actually the truncation of A051340 to its lower left triangular part, reindexed to start rows and columns with 1.  M. F. Hasler, Aug 15 2015


LINKS

Table of n, a(n) for n=1..102.


FORMULA

Truncation of A051340 to its lower left. By rows, "n" followed by (n1) 1's. (1,2,3...) in the left border, all 1's in other columns.
A130296^2 = A130297.
a(n) = A004201(n)  A004201(n1) for n>1.  Reinhard Zumkeller, Jul 16 2008


EXAMPLE

First few rows of the triangle are:
1;
2, 1;
3, 1, 1;
4, 1, 1, 1;
5, 1, 1, 1, 1;
...


PROG

(PARI) A130296(i, j)=if(j==1, i, j<=i) \\ The sequence should not be defined for j>i but it is used in several places as infinite square matrix with upper right part equal to zero.  M. F. Hasler, Aug 15 2015


CROSSREFS

Cf. A051340, A130297, A005408 (row sums).
Sequence in context: A300322 A144220 A156826 * A126705 A263646 A113924
Adjacent sequences: A130293 A130294 A130295 * A130297 A130298 A130299


KEYWORD

nonn,tabl,easy


AUTHOR

Gary W. Adamson, May 20 2007


STATUS

approved



