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Partial sums of A004111.
2

%I #22 Dec 26 2020 08:42:40

%S 0,1,2,3,5,8,14,26,51,103,216,463,1011,2237,5007,11306,25732,58941,

%T 135792,314410,731258,1707554,4001778,9409162,22189556,52472676,

%U 124397323,295594279,703904947,1679567427,4015010504,9614519152,23060649590,55395487476

%N Partial sums of A004111.

%C A004111 is an important sequence and the OEIS should include various sequences derived from it.

%H Alois P. Heinz, <a href="/A196118/b196118.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) ~ c * A246169^n / n^(3/2), where c = 0.601433809400132103408618319570970615307211984303335915895942080355184647... - _Vaclav Kotesovec_, Dec 26 2020

%p with(numtheory):

%p b:= proc(n) option remember; `if`(n<2, n, add(b(n-k)*add(

%p b(d)*d*(-1)^(k/d+1), d=divisors(k)), k=1..n-1)/(n-1))

%p end:

%p a:= proc(n) option remember; b(n)+`if`(n>0, a(n-1), 0) end:

%p seq(a(n), n=0..50); # _Alois P. Heinz_, Feb 24 2015

%t b[n_] := b[n] = If[n<2, n, Sum[b[n-k]*Sum[b[d]*d*(-1)^(k/d+1), {d, Divisors[k]}], {k, 1, n-1}]/(n-1)]; a[n_] := a[n] = b[n] + If[n>0, a[n-1], 0]; Table[a[n], {n, 0, 50}] (* _Jean-François Alcover_, Feb 17 2016, after _Alois P. Heinz_ *)

%Y Cf. A004111, A196154, A196161.

%K nonn

%O 0,3

%A _N. J. A. Sloane_, Oct 27 2011