

A213168


a(n) = n!/2  (n1)!  n + 2.


2



0, 0, 4, 33, 236, 1795, 15114, 141113, 1451512, 16329591, 199583990, 2634508789, 37362124788, 566658892787, 9153720575986, 156920924159985, 2845499424767984, 54420176498687983, 1094805903679487982, 23112569077678079981, 510909421717094399980
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OFFSET

2,3


COMMENTS

Row sums of A142706 for k=1..n1.


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 2..200


FORMULA

a(n) = A001286(n1)  n + 2.  Anton Zakharov, Sep 08 2016


MATHEMATICA

Table[n!/2  (n  1)!  n + 2, {n, 2, 20}]


PROG

(Maxima) A213168(n):=n!/2(n1)!n+2$
makelist(A213168(n), n, 2, 30); /* Martin Ettl, Nov 03 2012 */
(MAGMA) [Factorial(n)/2Factorial(n1)n+2: n in [2..25]]; // Vincenzo Librandi, Sep 09 2016


CROSSREFS

Cf. A001286.
Cf. A142706, A051683, A152883.
Cf. A200748 (considered as a triangular array).
Sequence in context: A131509 A221030 A081007 * A203212 A088317 A041024
Adjacent sequences: A213165 A213166 A213167 * A213169 A213170 A213171


KEYWORD

nonn,easy


AUTHOR

Olivier Gérard, Nov 02 2012


STATUS

approved



