OFFSET
1,11
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
N. J. A. Sloane, Transforms
MAPLE
with(numtheory): ietr:= proc(p) local a, c; c:= proc(n) option remember; local j; n*p(n)-add(c(j)*p(n-j), j=1..n-1) end; a:=proc(n) option remember; local d; `if`(n=0, 1, add(mobius(n/d)*c(d), d=divisors(n))/n) end end: aa:= ietr('a'): a:= n-> `if`(n<=1, 1, aa(n-1)): seq(a(n), n=1..48); # Alois P. Heinz, Sep 08 2008
MATHEMATICA
ietr[p_] := Module[{a, c},
c[n_] := c[n] = n*p[n] - Sum[c[j]*p[n-j], {j, 1, n-1}];
a[n_] := a[n] = If[n == 0, 1, Sum[MoebiusMu[n/d]*c[d],
{d, Divisors[n]}]/n]; a];
aa = ietr[a];
a[n_] := If[n <= 1, 1, aa[n-1]];
Array[a, 48] (* Jean-François Alcover, Mar 01 2021, after Alois P. Heinz *)
CROSSREFS
KEYWORD
sign,eigen
AUTHOR
Christian G. Bower, Jan 04 1999
STATUS
approved