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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A253273 Triangle read by rows: T(n,k) = Sum_{m=0..n-k+1} C(k+m,k-m+1)*C(n-k,m-1). 0
1, 1, 2, 1, 3, 3, 1, 4, 7, 4, 1, 5, 12, 14, 5, 1, 6, 18, 30, 25, 6, 1, 7, 25, 53, 66, 41, 7, 1, 8, 33, 84, 136, 132, 63, 8, 1, 9, 42, 124, 244, 315, 245, 92, 9, 1, 10, 52, 174, 400, 636, 673, 428, 129, 10, 1, 11, 63, 235, 615, 1152, 1522, 1346, 711, 175, 11 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..65.

FORMULA

G.f.: -1/((x-1)*y^2+(2-x)*y+x-1).

EXAMPLE

1;

1, 2;

1, 3, 3;

1, 4, 7, 4;

1, 5, 12, 14, 5;

1, 6, 18, 30, 25, 6;

1, 7, 25, 53, 66, 41, 7;

PROG

(Maxima)

T(n, m):=sum(binomial(m+k, m-k+1)*binomial(n-m, k-1), k, 0, n-m+1);

CROSSREFS

Row sums give A095263(n+1).

Sequence in context: A319539 A098546 A126277 * A055129 A133804 A185943

Adjacent sequences:  A253270 A253271 A253272 * A253274 A253275 A253276

KEYWORD

nonn,tabl

AUTHOR

Vladimir Kruchinin, May 01 2015

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 17 18:24 EST 2019. Contains 329241 sequences. (Running on oeis4.)