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Array read by rows: row n lists divisors of n-th positive triangular number A000217(n).
1

%I #2 Mar 30 2012 17:33:54

%S 1,1,3,1,2,3,6,1,2,5,10,1,3,5,15,1,3,7,21,1,2,4,7,14,28,1,2,3,4,6,9,

%T 12,18,36,1,3,5,9,15,45,1,5,11,55,1,2,3,6,11,22,33,66,1,2,3,6,13,26,

%U 39,78,1,7,13,91,1,3,5,7,15,21,35,105

%N Array read by rows: row n lists divisors of n-th positive triangular number A000217(n).

%e Array begins:

%e 1

%e 1, 3

%e 1, 2, 3, 6

%e 1, 2, 5, 10

%e 1, 3, 5, 15

%e 1, 3, 7, 21

%e 1, 2, 4, 7, 14, 28

%Y Cf. A000217, A133021, A133031, A138882.

%K easy,nonn,tabf

%O 1,3

%A _Omar E. Pol_, Apr 11 2008