A144470 - OEIS

A144470

Triangle t(n,m) read by rows: t(n,m) = binomial(n,m)*3^m if m <= n/2, else t(n,m) = t(n,n-m).

1, 1, 1, 1, 6, 1, 1, 9, 9, 1, 1, 12, 54, 12, 1, 1, 15, 90, 90, 15, 1, 1, 18, 135, 540, 135, 18, 1, 1, 21, 189, 945, 945, 189, 21, 1, 1, 24, 252, 1512, 5670, 1512, 252, 24, 1, 1, 27, 324, 2268, 10206, 10206, 2268, 324, 27, 1, 1, 30, 405, 3240, 17010, 61236, 17010, 3240

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OFFSET

0,5

COMMENTS

The row sums are 1, 2, 8, 20, 80, 212, 848, 2312, 9248, 25652, 102608, ...

LINKS

Table of n, a(n) for n=0..62.

FORMULA

t(n,m) = binomial(n,m)*3^m if 0 <= m <= n/2, t(n,m) = binomial(n,m)*3^(n-m) if n/2 < m <= n.

EXAMPLE

1, 1;

1, 6, 1;

1, 9, 9, 1;

1, 12, 54, 12, 1;

1, 15, 90, 90, 15, 1;

1, 18, 135, 540, 135, 18, 1;

1, 21, 189, 945, 945, 189, 21, 1;

1, 24, 252, 1512, 5670, 1512, 252, 24, 1;

1, 27, 324, 2268, 10206, 10206, 2268, 324, 27, 1;

1, 30, 405, 3240, 17010, 61236, 17010, 3240, 405, 30, 1;

MAPLE

A144470 := proc(n, m) if m <= floor(n/2) then binomial(n, m)*3^m ; else procname(n, n-m) ; end if; end proc: # R. J. Mathar, Feb 03 2011

MATHEMATICA

f[n_, m_] = If[m <= Floor[n/2], m, n - m]; Table[Table[Binomial[n, m]*3^f[n, m], {m, 0, n}], {n, 0, 10}]; Flatten[%]

CROSSREFS

Sequence in context: A132047 A140284 A143087 * A174377 A176151 A204001

Adjacent sequences: A144467 A144468 A144469 * A144471 A144472 A144473

KEYWORD

nonn,tabl,easy

AUTHOR

Roger L. Bagula and Gary W. Adamson, Oct 09 2008

STATUS

approved