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A078807 Triangular array T given by T(n,k) = number of 01-words of length n having exactly k 1's, all runlengths odd and first letter 0. 2
0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 2, 1, 1, 0, 0, 1, 2, 2, 2, 1, 1, 3, 3, 3, 2, 1, 0, 0, 1, 3, 4, 5, 4, 3, 1, 1, 4, 6, 7, 7, 5, 3, 1, 0, 0, 1, 4, 7, 10, 11, 10, 7, 4, 1, 1, 5, 10, 14, 17, 16, 13, 8, 4, 1, 0, 0, 1, 5, 11, 18, 24, 26, 24, 18, 11, 5, 1, 1, 6, 15, 25, 35, 40, 39, 32, 22, 12, 5, 1, 0, 0 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,13

COMMENTS

Row sums: 0,1,1,2,3,5,8,13,..., the Fibonacci numbers (A000045).

REFERENCES

Clark Kimberling, Binary words with restricted repetitions and associated compositions of integers, in Applications of Fibonacci Numbers, vol.10, Proceedings of the Eleventh International Conference on Fibonacci Numbers and Their Applications, William Webb, editor, Congressus Numerantium, Winnipeg, Manitoba 194 (2009) 141-151.

FORMULA

T(n, k)=T(n-1, n-k-1)+T(n-3, n-k-3)+...+T(n-2m-1, n-k-2m-1), where m=[(n-1)/2] and (by definition) T(i, j)=0 if i<0 or j<0 or i=j.

EXAMPLE

T(6,2) counts the words 010001 and 000101. Top of triangle:

0 = T(0,0)

1 = T(1,0)

0 1 = T(2,0) T(2,1)

1 1 0

0 1 1 1

1 2 1 1 0

CROSSREFS

Cf. A078808, A078821.

Sequence in context: A113447 A137608 A191336 * A029422 A152800 A117452

Adjacent sequences:  A078804 A078805 A078806 * A078808 A078809 A078810

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu), Dec 07 2002

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.