OFFSET
0,4
COMMENTS
The number of different ways to run up a staircase with 9 steps, taking steps of odd sizes (or taking steps of distinct sizes), where the order is not relevant and there is no other restriction on the number or the size of each step taken is the coefficient of x^9. - Mohammad K. Azarian, Aug 22 2010
REFERENCES
Mohammad K. Azarian, A Generalization of the Climbing Stairs Problem II, Missouri Journal of Mathematical Sciences, Vol. 16, No. 1, Winter 2004, pp. 12-17. Zentralblatt MATH, Zbl 1071.05501. - Mohammad K. Azarian, Aug 22 2010
Mohammad K. Azarian, A Generalization of the Climbing Stairs Problem, Mathematics and Computer Education, Vol. 31, No. 1, pp. 24-28, Winter 1997. MathEduc Database (Zentralblatt MATH, 1997c.01891). - Mohammad K. Azarian, Aug 22 2010
FORMULA
Expansion of (1+x)(1+x^2)(1+x^3)...(1+x^9).
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved