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A173279 Irregular triangle read by rows: M(n,k) = (n-2*k)!, k=0..floor(n/2). 2
1, 1, 2, 1, 6, 1, 24, 2, 1, 120, 6, 1, 720, 24, 2, 1, 5040, 120, 6, 1, 40320, 720, 24, 2, 1, 362880, 5040, 120, 6, 1, 3628800, 40320, 720, 24, 2, 1, 39916800, 362880, 5040, 120, 6, 1, 479001600, 3628800, 40320, 720, 24, 2, 1, 6227020800, 39916800, 362880, 5040, 120, 6, 1, 87178291200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

In the limit as j-> infinity, the power M^j approaches the limit described in A173280.

Row sums: sum_{k=0..n/2} M(n,k) = A136580(n).

LINKS

Table of n, a(n) for n=0..56.

EXAMPLE

Triangle starts in row n=0 as:

1;

1;

2, 1;

6, 1;

24, 2, 1;

120, 6, 1;

720, 24, 2, 1;

5040, 120, 6, 1;

40320, 720, 24, 2, 1;

362880, 5040, 120, 6, 1;

3628800, 40320, 720, 24, 2, 1;

39916800, 362880, 5040, 120, 6, 1;

479001600, 3628800, 40320, 720, 24, 2, 1;

...

MAPLE

A173279 := proc(n, k) factorial(n-2*k) ; end proc: seq(seq(A173279(n, k), k=0..floor(n/2)), n=0..20) ; # R. J. Mathar, Feb 22 2010

CROSSREFS

Cf. A000142, A136580, A173280

Sequence in context: A280736 A279095 A186283 * A277440 A083720 A055878

Adjacent sequences:  A173276 A173277 A173278 * A173280 A173281 A173282

KEYWORD

nonn,tabf

AUTHOR

Gary W. Adamson, Feb 14 2010

EXTENSIONS

keyword tabl replaced by tabf, R. J. Mathar, Feb 22 2010

STATUS

approved

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Last modified September 22 00:25 EDT 2017. Contains 292326 sequences.