OFFSET
1,5
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1275 (first 50 rows).
R. J. Mathar, Mixed Trees A335362
EXAMPLE
The triangle starts
1;
1, 1;
1, 2, 3;
2, 5,10, 8;
3,12,32,40,27;
There are T(3,1)=2 mixed trees on 3 nodes with one directed edge (the edge can point towards the middle node or away from it).
PROG
(PARI) \\ Here R(n) is rooted mixed trees as g.f.
EulerMTS(p)={my(n=serprec(p, x)-1, vars=variables(p)); exp(sum(i=1, n, substvec(p + O(x*x^(n\i)), vars, apply(v->v^i, vars))/i))}
R(n) = {my(p=x+O(x^2)); for(n=2, n, p=x*EulerMTS(2*y*p + p)); p}
T(n) = {my(p=R(n)); [Vecrev(p) | p<-Vec(p + (subst(subst(p + O(x*x^(n\2)), x, x^2), y, y^2) - (2*y+1)*p^2)/2)]}
{ my(A=T(10)); for(n=1, #A, print(A[n])) } \\ Andrew Howroyd, Mar 23 2023
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
R. J. Mathar, Jun 03 2020
EXTENSIONS
Completed row n=9. - R. J. Mathar, Jun 11 2020
Terms a(46) and beyond from Andrew Howroyd, Mar 23 2023
STATUS
approved