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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A034150 Number of partitions of n into distinct parts from [ 1, 20 ]. 1

%I

%S 1,1,1,2,2,3,4,5,6,8,10,12,15,18,22,27,32,38,46,54,64,75,87,101,117,

%T 135,155,178,203,231,263,297,335,378,424,475,531,591,657,729,806,889,

%U 980,1076,1180,1293,1411,1538,1674

%N Number of partitions of n into distinct parts from [ 1, 20 ].

%C The number of different ways to run up a staircase with 20 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^20. - _Mohammad K. Azarian_, Aug 22 2010

%D 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

%H Mohammad K. Azarian, <a href="http://www.math-cs.ucmo.edu/~mjms/2004.1/azar6.pdf">A Generalization of the Climbing Stairs Problem II</a>, 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

%F Expansion of (1+x)(1+x^2)(1+x^3)...(1+x^20).

%o (PARI) a(n) = polcoeff(prod(k=1, 20, 1 + x^k), n); \\ _Michel Marcus_, Mar 07 2015

%K nonn

%O 0,4

%A _N. J. A. Sloane_

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 13 14:58 EST 2017. Contains 295958 sequences.