|
| |
|
|
A115952
|
|
Expansion of (1-x+x*y)/(1-x^2*y^2)-x^2/(1-x^2*y).
|
|
3
| |
|
|
1, -1, 1, -1, 0, 1, 0, 0, -1, 1, 0, -1, 0, 0, 1, 0, 0, 0, 0, -1, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, -1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, -1
(list; table; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
COMMENTS
| Row sums are A000007. Diagonal sums are A115953. Inverse is A115954.
|
|
|
FORMULA
| Number triangle T(n,k)=if(n=k,1,0) OR if(n=2k+2,-1,0) OR if(n=k+1,-(1+(-1)^k)/2,0).
|
|
|
EXAMPLE
| Triangle begins
1,
-1, 1,
-1, 0, 1,
0, 0, -1, 1,
0, -1, 0, 0, 1,
0, 0, 0, 0, -1, 1,
0, 0, -1, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, -1, 1,
0, 0, 0, -1, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1,
0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1
|
|
|
CROSSREFS
| Cf. A115524.
Sequence in context: A010056 A155898 A181650 * A115524 A117198 A054525
Adjacent sequences: A115949 A115950 A115951 * A115953 A115954 A115955
|
|
|
KEYWORD
| easy,sign,tabl
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Feb 02 2006
|
| |
|
|
