OFFSET
0,4
LINKS
V. E. Adler, Set partitions and integrable hierarchies, arXiv:1510.02900 [nlin.SI], 2015.
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
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 12 2004
STATUS
approved