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 A124929 Triangle read by rows: T(n,k)=(2^k-1)binom(n-1,k-1) (1<=k<=n). 2

%I

%S 1,1,3,1,6,7,1,9,21,15,1,12,42,60,31,1,15,70,150,155,63,1,18,105,300,

%T 465,378,127,1,21,147,525,1085,1323,889,255,1,24,196,840,2170,3528,

%U 3556,2040,511,1,27,252,1260,3906,7938,10668,9180,4599,1023,1,30,315,1800

%N Triangle read by rows: T(n,k)=(2^k-1)binom(n-1,k-1) (1<=k<=n).

%C Row sums = 2*(3^n) - 2^n = A027649: (1, 4, 14, 46, 146...).

%e First few rows of the triangle are:

%e 1;

%e 1, 3;

%e 1, 6, 7;

%e 1, 9, 21, 15;

%e 1, 12, 42, 60, 31;

%e 1, 15, 70, 150, 155, 127;

%e ...

%p T:=(n,k)->(2^k-1)*binomial(n-1,k-1): for n from 1 to 11 do seq(T(n,k),k=1..n) od; # yields sequence in triangular form

%Y Cf. A027649.

%K nonn,tabl

%O 1,3

%A _Gary W. Adamson_, Nov 12 2006

%E Edited by _N. J. A. Sloane_, Nov 29 2006

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