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 A127571 Triangle T(n,k) = phi(n/k)*sigma(k) if k divides n, else 0. 0
 1, 1, 3, 2, 0, 4, 2, 3, 0, 7, 4, 0, 0, 0, 6, 2, 6, 4, 0, 0, 12, 6, 0, 0, 0, 0, 0, 8, 4, 6, 0, 7, 0, 0, 0, 15, 6, 0, 8, 0, 0, 0, 0, 0, 13, 4, 12, 0, 0, 6, 0, 0, 0, 0, 18 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA T(n,k) = sum_{j=k..n} A054523(n,j)* A130208(j,k), product of the two infinite lower triangular matrices. T(n,1) = A000010(n). T(n,n) = A000203(n). EXAMPLE First few rows of the triangle are: 1; 1, 3; 2, 0, 4; 2, 3, 0, 7; 4, 0, 0, 0, 6; 2, 6, 4, 0, 0, 12; ... CROSSREFS Cf. A000203, A000010, A038040 (row sums), A054523. Sequence in context: A275622 A129239 A224825 * A194662 A143612 A011231 Adjacent sequences:  A127568 A127569 A127570 * A127572 A127573 A127574 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Jan 19 2007 STATUS approved

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