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A127572 Triangle, T(n,k) = sigma(k) * n/k if k|n, T(n,k) = 0 otherwise. 0

%I #6 Mar 30 2012 17:35:17

%S 1,2,3,3,0,4,4,6,0,7,5,0,0,0,6,6,9,8,0,0,12,7,0,0,0,0,0,8,8,12,0,14,0,

%T 0,0,15,9,0,12,0,0,0,0,0,13,10,15,0,0,12,0,0,0,0,18

%N Triangle, T(n,k) = sigma(k) * n/k if k|n, T(n,k) = 0 otherwise.

%F A126988 * M, where M = an infinite matrix with sigma(n) in the main diagonal and the rest zeros.

%e First few rows of the triangle are:

%e 1;

%e 2, 3;

%e 3, 0, 4;

%e 4, 6, 0, 7;

%e 5, 0, 0, 0, 6;

%e 6, 9, 8, 0, 0, 12;

%e ...

%Y Main diagonal = sigma(n), A000203; row sums = A060640.

%Y Cf. A126988.

%K nonn,tabl

%O 1,2

%A _Gary W. Adamson_, Jan 19 2007

%E Edited by _Franklin T. Adams-Watters_, Aug 24 2011

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Last modified March 19 07:21 EDT 2024. Contains 370955 sequences. (Running on oeis4.)