



1, 1, 1, 3, 1, 1, 5, 3, 1, 1, 35, 5, 3, 1, 1, 63, 35, 5, 3, 1, 1, 231, 63, 35, 5, 3, 1, 1, 429, 231, 63, 35, 5, 3, 1, 1, 6435, 429, 231, 63, 35, 5, 3, 1, 1, 12155, 6435, 429, 231, 63, 35, 5, 3, 1, 1, 46189, 12155, 6435, 429, 231, 63, 35, 5, 3, 1, 1, 88179, 46189, 12155, 6435, 429
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,4


COMMENTS

Consider the fractional triangle A180955/A180956, call it triangle A. Consider also a triangle defined by k=1: T(n,1)=1, k>1 and n>=k: T(n,k)= any random number, else 0, call it triangle B. Calculate the matrix inverse of triangle B, call it triangle C. Multiply C with A, call the result triangle D. Calculate the matrix inverse of D, call it triangle E. Then the first column in both matrix A and matrix E will have the fraction A001790/A046161 in the first column.


LINKS

Table of n, a(n) for n=1..71.


EXAMPLE

Triangle starts:
1,
1,1,
3,1,1,
5,3,1,1,
35,5,3,1,1,
63,35,5,3,1,1,
231,63,35,5,3,1,1,
429,231,63,35,5,3,1,1,
6435,429,231,63,35,5,3,1,1,
12155,6435,429,231,63,35,5,3,1,1,
46189,12155,6435,429,231,63,35,5,3,1,1,
88179,46189,12155,6435,429,231,63,35,5,3,1,1,


CROSSREFS

Cf. A180956, A001790, A046161.
Sequence in context: A131247 A114278 A134836 * A349182 A191751 A285409
Adjacent sequences: A180952 A180953 A180954 * A180956 A180957 A180958


KEYWORD

nonn,tabl


AUTHOR

Mats Granvik, Sep 28 2010


STATUS

approved



