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A141432 Triangle T(n,k) = (k+1)*(n-k-1) read by rows, 1<=k<=n. 0
-2, 0, -3, 2, 0, -4, 4, 3, 0, -5, 6, 6, 4, 0, -6, 8, 9, 8, 5, 0, -7, 10, 12, 12, 10, 6, 0, -8, 12, 15, 16, 15, 12, 7, 0, -9, 14, 18, 20, 20, 18, 14, 8, 0, -10, 16, 21, 24, 25, 24, 21, 16, 9, 0, -11 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums are: -2, -3, -2, 2, 10, 23, 42, 68, 102, 145,  = n*(n^2-13)/6.

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

-2;

0, -3;

2, 0, -4;

4, 3, 0, -5;

6, 6, 4, 0, -6;

8, 9, 8, 5,0, -7;

10, 12, 12, 10, 6, 0, -8;

12, 15, 16, 15, 12, 7, 0, -9;

14, 18, 20, 20, 18, 14, 8, 0, -10;

16, 21, 24, 25, 24, 21, 16, 9, 0, -11;

MATHEMATICA

Clear[T, n, m, a, l, k] T[n_, m_, k_, l_] = (m + l)*((2 - l)*n - m + k); k = -1; l = 1; a = Table[Table[T[n, m, k, l], {m, 1, n}], {n, 1, 10}]; Flatten[a] Table[Sum[T[n, m, 1, 1], {m, 1, n}], {n, 1, 10}]; TableForm[a];

CROSSREFS

Cf. A003991, A004247.

Sequence in context: A127479 A284124 A187637 * A115241 A154559 A269133

Adjacent sequences:  A141429 A141430 A141431 * A141433 A141434 A141435

KEYWORD

tabl,easy,sign

AUTHOR

Roger L. Bagula and Gary W. Adamson, Aug 06 2008

STATUS

approved

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Last modified February 21 02:19 EST 2018. Contains 299388 sequences. (Running on oeis4.)