login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A242653 Triangle read by rows: T(n,k) = ((n+k)/2)!/k! if n,k have same parity, otherwise 0. 1
1, 0, 1, 1, 0, 1, 0, 2, 0, 1, 2, 0, 3, 0, 1, 0, 6, 0, 4, 0, 1, 6, 0, 12, 0, 5, 0, 1, 0, 24, 0, 20, 0, 6, 0, 1, 24, 0, 60, 0, 30, 0, 7, 0, 1, 0, 120, 0, 120, 0, 42, 0, 8, 0, 1, 120, 0, 360, 0, 210, 0, 56, 0, 9, 0, 1, 0, 720, 0, 840, 0, 336, 0, 72, 0, 10, 0, 1, 720, 0, 2520, 0, 1680, 0, 504 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,8

LINKS

Robert Israel, Table of n, a(n) for n = 0..10010

Alexander Kreinin, Combinatorial Properties of Mills' Ratio, arXiv:1405.5852, 2014. See Table 4.

EXAMPLE

Triangle begins:

1

0 1

1 0 1

0 2 0 1

2 0 3 0 1

0 6 0 4 0 1

6 0 12 0 5 0 1

0 24 0 20 0 6 0 1

...

MAPLE

N:= 1000; # to get a(0) to a(N)

count:= -1;

for n from 0 while count < N do

  for k from 0 to n while count  < N do

    count:= count+1;

    if type(n-k, even) then

       A[count]:= ((n+k)/2)!/k!

    else

       A[count]:= 0

    fi;

  od

od:

seq(A[i], i=0..N); # Robert Israel, Jun 10 2014

CROSSREFS

Sequence in context: A049803 A053121 A113408 * A191530 A173863 A022337

Adjacent sequences:  A242650 A242651 A242652 * A242654 A242655 A242656

KEYWORD

nonn,tabl,easy

AUTHOR

N. J. A. Sloane, May 29 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified February 17 16:26 EST 2018. Contains 299296 sequences. (Running on oeis4.)