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A155040 A symmetric (1,-1)-triangle. 1
1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Row sums are A007877(n+1). Diagonal sums are A155041.
LINKS
FORMULA
Number triangle T(n,k)=sum{j=0..n, [j<=k]*[j<=n-k]*(-1)*(((-1)^(j+1)-0^(j+1))-((-1)^j-0^j))}.
EXAMPLE
Triangle begins
.1,
.1, 1,
.1, -1, 1,
.1, -1, -1, 1,
.1, -1, 1, -1, 1,
.1, -1, 1, 1, -1, 1,
.1, -1, 1, -1, 1, -1, 1,
.1, -1, 1, -1, -1, 1, -1, 1,
.1, -1, 1, -1, 1, -1, 1, -1, 1,
.1, -1, 1, -1, 1, 1, -1, 1, -1, 1,
.1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1,
.1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1
CROSSREFS
Sequence in context: A246016 A306638 A076479 * A209661 A033999 A000012
KEYWORD
easy,sign,tabl
AUTHOR
Paul Barry, Jan 19 2009
STATUS
approved

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Last modified March 19 03:30 EDT 2024. Contains 370952 sequences. (Running on oeis4.)