%I #5 Mar 30 2012 17:34:34
%S 1,1,1,1,1,1,1,1,1,1,1,2,2,2,1,1,1,1,1,1,1,1,2,2,2,2,2,1,1,1,1,1,1,1,
%T 1,1,1,2,2,2,2,2,2,2,1,1,3,4,4,4,4,4,4,3,1,1,4,7,8,8,8,8,8,7,4,1,1,1,
%U 1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
%N Triangle T(n,k) read by rows: T(n,k)=1 if the row index n is prime or <=1, otherwise T(n,k) = T(n-1,k)+T(n-1,k-1).
%C Row sums are: 1, 2, 3, 4, 8, 6, 12, 8, 16, 32, 64, 12, 24, 14, 28, 56,...
%e 1;
%e 1, 1;
%e 1, 1, 1;
%e 1, 1, 1, 1;
%e 1, 2, 2, 2, 1;
%e 1, 1, 1, 1, 1, 1;
%e 1, 2, 2, 2, 2, 2, 1;
%e 1, 1, 1, 1, 1, 1, 1, 1;
%e 1, 2, 2, 2, 2, 2, 2, 2, 1;
%e 1, 3, 4, 4, 4, 4, 4, 4, 3, 1;
%e 1, 4, 7, 8, 8, 8, 8, 8, 7, 4, 1;
%e 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1;
%e 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1;
%e 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1;
%e 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1;
%e 1, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 1;
%t Clear[p, x, n, a];
%t p[x, 0] = 1; p[x, 1] = ((x + 1)); p[x, 2] = ((x^2 + x + 1));
%t p[x_, n_] := p[x, n] = If[PrimeQ[n], Sum[x^i, {i, 0, n}], (x + 1)*p[x, n - 1]];
%t a = Table[CoefficientList[FullSimplify[p[x, n]], x], {n, 0, 15}];
%t Flatten[a]
%K nonn,tabl,easy
%O 0,12
%A _Roger L. Bagula_, Feb 27 2009