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Triangle read by rows: T(n,k)=binomial(n-2k,3k+2) (n>=2, 0<=k<=(n-2)/5).
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%I #4 Mar 07 2013 19:33:25

%S 1,3,6,10,15,21,1,28,6,36,21,45,56,55,126,66,252,1,78,462,9,91,792,45,

%T 105,1287,165,120,2002,495,136,3003,1287,1,153,4368,3003,12,171,6188,

%U 6435,78,190,8568,12870,364

%N Triangle read by rows: T(n,k)=binomial(n-2k,3k+2) (n>=2, 0<=k<=(n-2)/5).

%C Row n contains floor((n+3)/5) terms.

%C Row sums yield A137358.

%D D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.4.

%p T:=proc(n,k) options operator, arrow: binomial(n-2*k,3*k+2) end proc: for n from 2 to 20 do seq(T(n,k),k=0..(n-2)*1/5) end do; # yields sequence in triangular form

%t Flatten[Table[Binomial[n-2k,3k+2],{n,2,20},{k,0,(n-2)/5}]] (* _Harvey P. Dale_, Mar 07 2013 *)

%Y Cf. A137358.

%K nonn,tabf

%O 2,2

%A _Emeric Deutsch_, May 10 2008