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Search: id:A117904
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| A117904 |
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Number triangle [k<=n]*0^abs(L(C(n,2)/3)-L(C(k,2)/3)) where L(j/p) is the Legendre symbol of j and p. |
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+0
5
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| 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1
(list; table; graph; listen)
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OFFSET
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0,1
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COMMENT
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Row sums are A009947(n+2). Diagonal sums are A117905. Inverse is A117906. Equal to A117898 mod 2.
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FORMULA
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G.f.: (1+x(1+y)+x^2*y^2+x^3*y)/((1-x^3)(1-x^3*y^3)) T(n,k):=mod([k<=n]*2^abs(L(C(n,2)/3)-L(C(k,2)/3)),2);
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EXAMPLE
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Triangle begins
1,
1, 1,
0, 0, 1,
1, 1, 0, 1,
1, 1, 0, 1, 1,
0, 0, 1, 0, 0, 1,
1, 1, 0, 1, 1, 0, 1,
1, 1, 0, 1, 1, 0, 1, 1,
0, 0, 1, 0, 0, 1, 0, 0, 1,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1
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CROSSREFS
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Sequence in context: A016410 A115361 A115358 this_sequence A115944 A071003 A071002
Adjacent sequences: A117901 A117902 A117903 this_sequence A117905 A117906 A117907
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Apr 01 2006
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