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Construct a triangle T(n,k) (0 <= k <= n) of strings of integers, where T(0,0) = {0}, T(n,n) = {n}, and otherwise T(n,k) is the concatenation of T(n-1,k-1) and T(n-1,k). The sequence is obtained by reading across the rows of the triangle, concatenating the successive strings.
1

%I #13 Nov 05 2017 19:25:29

%S 0,0,1,0,0,1,2,0,0,0,1,0,1,2,3,0,0,0,0,1,0,0,1,0,1,2,0,1,2,3,4,0,0,0,

%T 0,0,1,0,0,0,1,0,0,1,0,1,2,0,0,1,0,1,2,0,1,2,3,0,1,2,3,4,5,0,0,0,0,0,

%U 0,1,0,0,0,0,1,0,0,0,1,0,0,1,0,1,2,0,0,0,1,0,0,1,0,1,2,0,0,1,0,1,2,0,1,2,3,0,0,1,0,1,2,0,1,2,3,0,1,2,3,4

%N Construct a triangle T(n,k) (0 <= k <= n) of strings of integers, where T(0,0) = {0}, T(n,n) = {n}, and otherwise T(n,k) is the concatenation of T(n-1,k-1) and T(n-1,k). The sequence is obtained by reading across the rows of the triangle, concatenating the successive strings.

%C The string T(n,k) contains binomial(n,k) numbers.

%e The first few rows of the triangle (where the strings T(n,k) are shown without spaces for legibility) are:

%e 0,

%e 0,1,

%e 0,01,2,

%e 0,001,012,3,

%e 0,0001,001012,0123,4,

%e 0,00001,0001001012,0010120123,01234,5,

%e ...

%Y Subtracting 1 from each term gives A265754.

%Y Cf. A007318.

%K nonn,tabf

%O 0,7

%A _N. J. A. Sloane_, Nov 05 2017