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A341710 a(n) = A120963(n)/2.

%I A341710 #16 Jul 09 2025 04:55:09
%S A341710 1,3,5,12,19,39,59,112,165,292,419,710,1001,1629,2257,3567,4877,7505,
%T A341710 10133,15266,20399,30140,39881,57983,76085,108981,141877,200625,
%U A341710 259373,362433,465493,643653,821813,1125269,1428725,1939149,2449573,3297411,4145249,5538254
%N A341710 a(n) = A120963(n)/2.
%p A341710 with(numtheory):
%p A341710 b:= proc(n) option remember; nops(invphi(n)) end:
%p A341710 a:= proc(n) option remember; `if`(n=0, 1/2, add(
%p A341710       a(n-j)*add(d*b(d), d=divisors(j)), j=1..n)/n)
%p A341710     end:
%p A341710 seq(a(n), n=1..40);  # _Alois P. Heinz_, Feb 19 2021
%t A341710 terms = 40;
%t A341710 S[m_] := S[m] = CoefficientList[Product[1/(1 - x^EulerPhi[k]),
%t A341710      {k, 1, m*terms}] + O[x]^(terms+1), x]/2 // Rest;
%t A341710 S[m = 1];
%t A341710 S[m++];
%t A341710 While[S[m] != S[m-1], m++];
%t A341710 S[m] (* _Jean-François Alcover_, May 12 2022 *)
%Y A341710 Cf. A120963, A341711, A341712.
%K A341710 nonn
%O A341710 1,2
%A A341710 _N. J. A. Sloane_, Feb 19 2021