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A154957
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A symmetric (0,1)-triangle.
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2
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1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1
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OFFSET
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0,1
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COMMENTS
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Row sums are A004524(n+3). Diagonal sums are A154958. Central coefficients are mod(n+1,2). T(2n,n)-T(2n,n+1)=(-1)^n.
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LINKS
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Table of n, a(n) for n=0..104.
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FORMULA
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Triangle T(n,k)=sum{j=0..n, [j<=k]*[j<=n-k]*(mod(j+1,2)-mod(j,2))}.
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EXAMPLE
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Triangle begins
1,
1, 1,
1, 0, 1,
1, 0, 0, 1,
1, 0, 1, 0, 1,
1, 0, 1, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1
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CROSSREFS
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Sequence in context: A131219 A127970 A158856 * A140865 A114000 A131218
Adjacent sequences: A154954 A154955 A154956 * A154958 A154959 A154960
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry, Jan 18 2009
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STATUS
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approved
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