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A127505
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Triangle T(n,k) = mobius(n/k)*phi(k) if k|n, otherwise T(n,k)=0; 1<=k<=n.
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0
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1, -1, 1, -1, 0, 2, 0, -1, 0, 2, -1, 0, 0, 0, 4, 1, -1, -2, 0, 0, 2, -1, 0, 0, 0, 0, 0, 6, 0, 0, 0, -2, 0, 0, 0, 4, 0, 0, -2, 0, 0, 0, 0, 0, 6, 1, -1, 0, 0, -4, 0, 0, 0, 0, 4, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 1, 0, -2, 0, -2, 0, 0
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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FORMULA
| T(n,k) = sum_{j=k..n} A054525(n,j)*A130207(j,k), 1<=k<=n.
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EXAMPLE
| First few rows of the triangle are:
1;
-1, 1;
-1, 0, 2;
0, -1, 0, 2;
-1, 0, 0, 0, 4;
1, -1, -2, 0, 0, 2;
...
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CROSSREFS
| Cf. A051731, A000010 (diagonal n=k), A007431 (row sums), A008683 (column k=1).
Sequence in context: A178090 A110914 A193527 * A194923 A086372 A089650
Adjacent sequences: A127502 A127503 A127504 * A127506 A127507 A127508
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KEYWORD
| easy,tabl,sign
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AUTHOR
| Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 17 2007
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