This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A122851 Number triangle T(n,k) = C(k,n-k)*(n-k)!. 1

%I

%S 1,0,1,0,1,1,0,0,2,1,0,0,2,3,1,0,0,0,6,4,1,0,0,0,6,12,5,1,0,0,0,0,24,

%T 20,6,1,0,0,0,0,24,60,30,7,1,0,0,0,0,0,120,120,42,8,1,0,0,0,0,0,120,

%U 360,210,56,9,1

%N Number triangle T(n,k) = C(k,n-k)*(n-k)!.

%C Row sums are A122852.

%C Triangle T(n,k), read by rows, given by (0,1,-1,0,0,1,-1,0,0,1,-1,0,0,1,...) DELTA (1,0,0,-1,2,0,0,-2,3,0,0,-3,4,...) where DELTA is the operator defined in A084938. - _Philippe DelĂ©ham_, Dec 12 2011

%F Number triangle T(n,k)=[k<=n]*k!/(2k-n)!.

%F T(n,k) = A008279(k,n-k). - _Danny Rorabaugh_, Apr 23 2015

%e Triangle begins

%e 1,

%e 0, 1,

%e 0, 1, 1,

%e 0, 0, 2, 1,

%e 0, 0, 2, 3, 1,

%e 0, 0, 0, 6, 4, 1,

%e 0, 0, 0, 6, 12, 5, 1,

%e 0, 0, 0, 0, 24, 20, 6, 1

%t Flatten[Table[Binomial[k,n-k](n-k)!,{n,0,10},{k,0,n}]] _Harvey P. Dale_, May 16 2012

%o (MAGMA) /* As triangle: */ [[Binomial(k,n-k)*Factorial(n-k): k in [0..n]]: n in [0.. 7]]; // _Vincenzo Librandi_, Apr 24 2015

%Y Cf. A094587.

%K nonn,tabl,easy

%O 0,9

%A _Paul Barry_, Sep 14 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 18 00:19 EST 2019. Contains 320237 sequences. (Running on oeis4.)