login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A099950 Number of 2-sparse nonoverlapping partitions of n. 0
1, 1, 1, 2, 4, 10, 27, 80, 255, 870, 3155, 12100, 48871, 207162, 918944, 4254690, 20513838, 102784942, 534205629, 2875098840, 15999114433, 91923562922, 544606671776, 3323112062994, 20860869818386, 134585869671342 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..25.

V. E. Adler, Set partitions and integrable hierarchies, arXiv:1510.02900 [nlin.SI], 2015.

M. Klazar, Bell numbers, their relatives and algebraic differential equations

M. Klazar, Bell numbers, their relatives and algebraic differential equations, J. Combin. Theory, A 102 (2003), 63-87.

PROG

(PARI) {a(n)=local(A); if(n<0, 0, A=O(x^0); for(i=0, n\2, A=(1+x)/(1-x^2*subst(A, x, x/(1-x)))); polcoeff(A, n))} /* Michael Somos, Sep 22 2005 */

CROSSREFS

Sequence in context: A148106 A291210 A340635 * A121690 A138356 A287693

Adjacent sequences:  A099947 A099948 A099949 * A099951 A099952 A099953

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 12 2004

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 May 18 19:29 EDT 2021. Contains 344002 sequences. (Running on oeis4.)