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 A057772 Inverse Euler transform of A000016. 1
 1, 0, 1, 0, 2, 1, 4, 4, 12, 15, 34, 55, 110, 190, 370, 664, 1272, 2350, 4466, 8372, 15926, 30105, 57390, 109202, 208738, 398985, 764906, 1467370, 2820770, 5427543, 10459456, 20176561, 38969684, 75339232, 145804978, 282429242, 547573768, 1062501151, 2063317650 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 REFERENCES P. J. Cameron, Some counting problems related to permutation groups, Discrete Math., 225 (2000), 77-92. LINKS Alois P. Heinz, Table of n, a(n) for n = 1..1000 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: a:= ietr(n-> add(phi(d) *2^(n/d)/2/n, d=select(m-> modp(m, 2)=1, divisors(n)))): seq(a(n), n=1..40); # Alois P. Heinz, Sep 08 2008 MATHEMATICA ietr[p_] := Module[{a, c}, c[n_] := c[n] = Module[{j}, n*p[n] - Sum[c[j]*p[n-j], {j, 1, n-1}]]; a[n_] := a[n] = Module[{d}, If[n == 0, 1, Sum[MoebiusMu[n/d]*c[d], {d, Divisors[n]}]/n]]; a]; a = ietr[Function[n, Sum[EulerPhi[d]*2^(n/d)/2/n, {d, Select[Divisors[n], OddQ]}]]]; Table[a[n], {n, 1, 40}] (* Jean-François Alcover, Jan 17 2014, after Alois P. Heinz *) CROSSREFS Sequence in context: A211178 A048049 A212716 * A145861 A191660 A129874 Adjacent sequences:  A057769 A057770 A057771 * A057773 A057774 A057775 KEYWORD nonn AUTHOR N. J. A. Sloane, Nov 02 2000 EXTENSIONS Better definition and more terms from Vladeta Jovovic, Mar 13 2008 STATUS approved

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Last modified August 4 02:10 EDT 2020. Contains 336201 sequences. (Running on oeis4.)