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Triangle, read by rows, where T(n,k) = C(n,k)*(C(n,k) + 1)/2, n>=k>=0.
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%I #15 Jun 04 2013 15:49:46

%S 1,1,1,1,3,1,1,6,6,1,1,10,21,10,1,1,15,55,55,15,1,1,21,120,210,120,21,

%T 1,1,28,231,630,630,231,28,1,1,36,406,1596,2485,1596,406,36,1,1,45,

%U 666,3570,8001,8001,3570,666,45,1,1,55,1035,7260,22155,31878,22155,7260

%N Triangle, read by rows, where T(n,k) = C(n,k)*(C(n,k) + 1)/2, n>=k>=0.

%C Replace each number x in Pascal's triangle by x(x+1)/2. - _Charlie Marion_, May 31 2013

%F n-th row sum equals A005317(n) = (C(2n, n) + 2^n)/2.

%e Triangle begins:

%e 1;

%e 1,1;

%e 1,3,1;

%e 1,6,6,1;

%e 1,10,21,10,1;

%e 1,15,55,55,15,1;

%e 1,21,120,210,120,21,1;

%e 1,28,231,630,630,231,28,1; ...

%o (PARI) T(n,k)=binomial(n,k)*(binomial(n,k)+1)/2

%Y Cf. A005317 (row sums), A107597 (antidiagonal sums).

%K nonn,tabl,easy

%O 0,5

%A _Paul D. Hanna_, May 21 2005