login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A047120 Array T read by diagonals: T(h,k)=number of paths consisting of steps from (0,0) to (h,k) such that each step has length 1 directed up or right and touches the line y=x/4 only at lattice points. 9

%I

%S 1,1,1,1,1,1,1,2,1,1,1,3,3,1,1,1,4,6,4,2,1,1,5,10,10,6,3,1,1,6,15,20,

%T 16,6,4,1,1,7,21,35,36,22,6,5,1,1,8,28,56,71,58,28,6,6,1,1,9,36,84,

%U 127,129,86,34,12,7,1,1,10,45,120,211,256,215,120,46,19,8,1

%N Array T read by diagonals: T(h,k)=number of paths consisting of steps from (0,0) to (h,k) such that each step has length 1 directed up or right and touches the line y=x/4 only at lattice points.

%t T[_, 0] = 1; T[0, _] = 1; T[h_, k_] := T[h, k] = If[k-1 >= h/4 || k <= h/4, T[h, k-1], 0] + T[h-1, k];

%t Table[T[h - k, k], {h, 0, 11}, {k, h, 0, -1}] // Flatten (* _Jean-Fran├žois Alcover_, Mar 06 2019 *)

%Y Cf. A047089 (with y=x/2), A047100 (with y=x/3).

%K nonn,tabl

%O 0,8

%A _Clark Kimberling_

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 January 27 12:50 EST 2022. Contains 350607 sequences. (Running on oeis4.)