OFFSET
0,5
PROG
(PARI)
OrderCycs(v)={my(t=vector(#v), L=List()); for(i=1, #v, my(c=0, j=i); while(!t[j], t[j]=1; j=v[j]; c++); if(c, listput(L, c))); Vec(L)}
a(n)={my(u=vecsort([Vecsmall(Vecrev(p)) | p<-partitions(n)])); my(v=vecsort(u, (x, y)->lex(#x, #y), 1+4)); vecprod(Set(OrderCycs(v)))} \\ Andrew Howroyd, Sep 17 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Name changed to agree with data and a(0)=1 prepended by Andrew Howroyd, Sep 17 2019
STATUS
approved