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 A176791 Triangle t(n,m) read by rows: t(n,m) = binomial(2^n-1, 2^m-1) if n >= 2*m, otherwise symmetrically extended t(n,m) = t(n,n-m). 1

%I

%S 1,1,1,1,3,1,1,7,7,1,1,15,455,15,1,1,31,4495,4495,31,1,1,63,39711,

%T 553270671,39711,63,1,1,127,333375,89356415775,89356415775,333375,127,

%U 1,1,255,2731135,12801990477375,629921975126394617164575,12801990477375

%N Triangle t(n,m) read by rows: t(n,m) = binomial(2^n-1, 2^m-1) if n >= 2*m, otherwise symmetrically extended t(n,m) = t(n,n-m).

%C Row sums are 1, 2, 5, 16, 487, 9054, 553350221, 178713498556, 629921975151998603582107, 52571341051325843383483521914, ...

%e 1;

%e 1, 1;

%e 1, 3, 1;

%e 1, 7, 7, 1;

%e 1, 15, 455, 15, 1;

%e 1, 31, 4495, 4495, 31, 1;

%e 1, 63, 39711, 553270671, 39711, 63, 1;

%e 1, 127, 333375, 89356415775, 89356415775, 333375, 127, 1;

%e 1, 255, 2731135, 12801990477375, 629921975126394617164575, 12801990477375, 2731135, 255, 1

%p A176791 := proc(n,m)

%p if n >= 2*m then

%p binomial(2^n-1,2^m-1) ;

%p else

%p procname(n,n-m) ;

%p end if:

%p end proc: # _R. J. Mathar_, Jan 29 2012

%t t[n_, m_] := If[Floor[n/2] >= m, Binomial[2^n - 1, 2^m - 1], Binomial[2^n - 1, 2^(n - m) - 1]];

%t Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}];

%t Flatten[%]

%Y Cf. A174387.

%K nonn,tabl,easy

%O 0,5

%A _Roger L. Bagula_, Apr 26 2010

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Last modified August 24 18:52 EDT 2019. Contains 326295 sequences. (Running on oeis4.)