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Search: id:A117898
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| A117898 |
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Number triangle 2^abs(L(C(n,2)/3)-L(C(k,2)/3))*[k<=n] 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, 2, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1
(list; table; graph; listen)
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OFFSET
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0,4
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COMMENT
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Row sums are A117899. Diagonal sums are A117900. Inverse is A117901. A117898 mod 2 is A117904.
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FORMULA
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G.f.: (1+x(1+y)+x^2(2+2y+y^2)+x^3*y(1+2y)+2x^4*y^2)/((1-x^3)(1-x^3*y^3)); Number triangle [k<=n]*2^abs(L(C(n,2)/3)-L(C(k,2)/3))
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EXAMPLE
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Triangle begins
1,
1, 1,
2, 2, 1,
1, 1, 2, 1,
1, 1, 2, 1, 1,
2, 2, 1, 2, 2, 1,
1, 1, 2, 1, 1, 2, 1,
1, 1, 2, 1, 1, 2, 1, 1,
2, 2, 1, 2, 2, 1, 2, 2, 1,
1, 1, 2, 1, 1, 2, 1, 1, 2, 1,
1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1,
2, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1,
1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1
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CROSSREFS
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Sequence in context: A078082 A079674 A113193 this_sequence A072344 A140500 A030616
Adjacent sequences: A117895 A117896 A117897 this_sequence A117899 A117900 A117901
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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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