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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A120933 Triangle read by rows: T(n,k) is the number of binary words of length n for which the length of the maximal leading nondecreasing subword is k (1<=k<=n). 0
2, 1, 3, 2, 2, 4, 4, 4, 3, 5, 8, 8, 6, 4, 6, 16, 16, 12, 8, 5, 7, 32, 32, 24, 16, 10, 6, 8, 64, 64, 48, 32, 20, 12, 7, 9, 128, 128, 96, 64, 40, 24, 14, 8, 10, 256, 256, 192, 128, 80, 48, 28, 16, 9, 11, 512, 512, 384, 256, 160, 96, 56, 32, 18, 10, 12, 1024, 1024, 768, 512, 320 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums are the powers of 2 (A000079). Sum(k*T(n,k), k=1..n)=3*2^n-n-3=A095151(n).

LINKS

Table of n, a(n) for n=1..71.

FORMULA

T(n,k)=k*2^(n-k-1) if k<n; T(n,n)=n+1. G=G(t,z)=(1-2z+tz^2)/[(1-2z)(1-tz)^2] - 1.

EXAMPLE

T(4,2)=4 because we have 0100,0101,1100 and 1101.

Triangle starts:

2;

1,3;

2,2,4;

4,4,3,5;

8,8,6,4,6;

MAPLE

T:=proc(n, k) if k<n then k*2^(n-k-1) elif k=n then n+1 else 0 fi end: for n from 1 to 13 do seq(T(n, k), k=1..n) od; # yields sequence in triangular form;

CROSSREFS

Cf. A000079, A095151.

Sequence in context: A210553 A269456 A208906 * A209756 A210795 A210862

Adjacent sequences:  A120930 A120931 A120932 * A120934 A120935 A120936

KEYWORD

nonn,tabl

AUTHOR

Emeric Deutsch, Jul 16 2006

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 July 15 14:28 EDT 2019. Contains 325031 sequences. (Running on oeis4.)