A132427
Triangle, read by rows of 2n+1 terms, where T(n,k) = T(n,k-1) + T(n-1,k-2) for n>0, 10 and T(0,0)=1.
1, 1, 1, 2, 2, 2, 3, 4, 6, 6, 6, 8, 10, 13, 17, 23, 23, 23, 29, 35, 43, 53, 66, 83, 106, 106, 106, 129, 152, 181, 216, 259, 312, 378, 461, 567, 567, 567, 673, 779, 908, 1060, 1241, 1457, 1716, 2028, 2406, 2867, 3434, 3434, 3434, 4001, 4568, 5241, 6020, 6928, 7988
Offset: 0
Examples
Triangle begins: 1; 1, 1, 2; 2, 2, 3, 4, 6; 6, 6, 8, 10, 13, 17, 23; 23, 23, 29, 35, 43, 53, 66, 83, 106; 106, 106, 129, 152, 181, 216, 259, 312, 378, 461, 567; 567, 567, 673, 779, 908, 1060, 1241, 1457, 1716, 2028, 2406, 2867, 3434; ...
Programs
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Mathematica
t[n_, k_] := t[n, k] = t[n, k-1] + t[n-1, k-2]; t[n_, 0] := t[n, 0] = t[n-1, 2n-2]; t[n_, 1] := t[n, 0]; t[0, 0] = 1; Flatten[ Table[t[n, k], {n, 0, 7}, {k, 0, 2 n}]] (* Jean-François Alcover, Jun 18 2012 *) -
PARI
T(n,k)=local(A=[1]);if(2*n
Comments