OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
N. J. A. Sloane, Transforms
MAPLE
b:= ((proc(p) local b; b:= proc(n) option remember; `if`(n=0, 1,
add(add(d*p(d), d=numtheory[divisors](j))*b(n-j), j=1..n)/n)
end end)@@3)(a):
a:= n-> b(n-1):
seq(a(n), n=0..25); # revised Alois P. Heinz, Aug 27 2018
MATHEMATICA
etr[p_] := Module[{b}, b[n_] := b[n] = If[n == 0, 1, Sum[Sum[d*p[d], {d, Divisors[ j]}]*b[n-j], {j, 1, n}]/n]; b]; A[n_, k_] := Module[{a, b, t}, b[1] = etr[a]; For[ t = 2, t <= k, t++, b[t] = etr[b[t-1]]]; a = Function[m, If[m == 1, 1, b[k][m-1]]]; a[n]]; Table[ A[n, 3], {n, 0, 30} ] (* Jean-François Alcover, Mar 05 2015, after Alois P. Heinz *)
CROSSREFS
KEYWORD
eigen,nonn
AUTHOR
Alois P. Heinz, Sep 07 2008
STATUS
approved