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 A127447 Triangle defined by the matrix product A127446 * A054521, read by rows 1<=k<=n. 1
 1, 4, 0, 6, 3, 0, 12, 0, 4, 0, 10, 5, 5, 5, 0, 24, 6, 0, 0, 6, 0, 14, 7, 7, 7, 7, 7, 0, 32, 0, 16, 0, 8, 0, 8, 0, 27, 18, 0, 9, 9, 0, 9, 9, 0, 40, 10, 20, 10, 0, 0, 10, 0, 10, 0, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 0, 72, 12, 12, 0, 24, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA T(n,k) = Sum_{j=k..n} A127446(n,j) * A054521(j,k). EXAMPLE First few rows of the triangle are: 1; 4, 0; 6, 3, 0; 12, 0, 4, 0; 10, 5, 5, 5, 0; 24, 6, 0, 0, 6, 0; 14, 7, 7, 7, 7, 7, 0; 32, 0, 16, 0, 8 0, 8, 0; ... MAPLE A054521 := proc(n, k) if igcd(n, k) = 1 then 1; else 0; fi; end: A127447 := proc(n, k)         add( A127446(n, j)*A054521(j, k), j=k..n) ; end proc: seq(seq(A127447(n, m), m=1..n), n=1..12) ; # R. J. Mathar, Nov 08 2011 CROSSREFS Cf. A038040 (column k=1), A000290 (row sums), A127446, A054521. Sequence in context: A085968 A010637 A200692 * A226775 A338682 A305731 Adjacent sequences:  A127444 A127445 A127446 * A127448 A127449 A127450 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Jan 14 2007 STATUS approved

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Last modified June 20 17:43 EDT 2021. Contains 345199 sequences. (Running on oeis4.)