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A118546 A symmetrical triangle of coefficient weights: A117662 :f(n)=n*(n - 1)*(n - 2)*(n + 3)/12; t(n,m)=f(n - m + 1)*f(m + 1). 0
9, 42, 42, 120, 196, 120, 270, 560, 560, 270, 525, 1260, 1600, 1260, 525, 924, 2450, 3600, 3600, 2450, 924, 1512, 4312, 7000, 8100, 7000, 4312, 1512, 2340, 7056, 12320, 15750, 15750, 12320, 7056, 2340, 3465, 10920, 20160, 27720, 30625, 27720, 20160 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums with zeros:

{0, 0, 9, 84, 436, 1660, 5170, 13948, 33748}.

REFERENCES

Steven Weinberg, Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity, John Wiley and Sons, Inc., New York, 1972, page145: Number of algebraic scalars constructed from curvature R(i,j,k,l) and metric ground form g(i,j):A117662.

LINKS

Table of n, a(n) for n=1..43.

FORMULA

f(n)=n*(n - 1)*(n - 2)*(n + 3)/12; t(n,m)=f(n - m + 1)*f(m + 1).

EXAMPLE

Initial Zeros removed:

{9},

{42, 42},

{120, 196, 120},

{270, 560, 560, 270},

{525, 1260, 1600, 1260, 525},

{924, 2450, 3600, 3600, 2450, 924},

{1512, 4312, 7000, 8100, 7000, 4312, 1512},

{2340, 7056, 12320, 15750, 15750, 12320, 7056, 2340},

{3465, 10920, 20160, 27720, 30625, 27720, 20160, 10920, 3465}

MATHEMATICA

f[n_] = n*(n - 1)*(n - 2)*(n + 3)/12; t[n_, m_] = f[n - m + 1]*f[m + 1]; Table[Table[t[n, m], {m, 2, n - 2}], {n, 2, 12}]; Flatten[%]

CROSSREFS

Cf. A117662.

Sequence in context: A235642 A050635 A065792 * A075233 A062783 A172464

Adjacent sequences:  A118543 A118544 A118545 * A118547 A118548 A118549

KEYWORD

nonn,tabl

AUTHOR

Roger L. Bagula and Gary W. Adamson, Aug 25 2008

STATUS

approved

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Last modified August 20 22:45 EDT 2019. Contains 326155 sequences. (Running on oeis4.)