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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
1, 1, 1, 1, 3, 1, 1, 7, 7, 1, 1, 15, 455, 15, 1, 1, 31, 4495, 4495, 31, 1, 1, 63, 39711, 553270671, 39711, 63, 1, 1, 127, 333375, 89356415775, 89356415775, 333375, 127, 1, 1, 255, 2731135, 12801990477375, 629921975126394617164575, 12801990477375 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

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

LINKS

Table of n, a(n) for n=0..41.

EXAMPLE

1;

1, 1;

1, 3, 1;

1, 7, 7, 1;

1, 15, 455, 15, 1;

1, 31, 4495, 4495, 31, 1;

1, 63, 39711, 553270671, 39711, 63, 1;

1, 127, 333375, 89356415775, 89356415775, 333375, 127, 1;

1, 255, 2731135, 12801990477375, 629921975126394617164575, 12801990477375, 2731135, 255, 1

MAPLE

A176791 := proc(n, m)

        if n >= 2*m then

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

        else

                procname(n, n-m) ;

        end if:

end proc: # R. J. Mathar, Jan 29 2012

MATHEMATICA

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

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

Flatten[%]

CROSSREFS

Cf. A174387.

Sequence in context: A057004 A059328 A174387 * A259471 A220555 A075440

Adjacent sequences:  A176788 A176789 A176790 * A176792 A176793 A176794

KEYWORD

nonn,tabl,easy

AUTHOR

Roger L. Bagula, Apr 26 2010

STATUS

approved

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Last modified July 21 19:13 EDT 2019. Contains 325199 sequences. (Running on oeis4.)