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Expansion of g.f. Sum_{n>=1} q^n/(1-q^n-q^(2*n)-q^(3*n)).
2

%I #6 Jan 03 2024 09:28:56

%S 1,2,3,6,8,17,25,50,84,158,275,525,928,1731,3146,5818,10610,19611,

%T 35891,66174,121442,223593,410745,756045,1389545,2556686,4700854,

%U 8647799,15902592,29252734,53798081,98955914,181997878,334756388,615693506,1132456971,2082876104,3831042321,7046320314,12960268134

%N Expansion of g.f. Sum_{n>=1} q^n/(1-q^n-q^(2*n)-q^(3*n)).

%o (PARI) my(N=55,q='q+O('q^N)); Vec(sum(n=1,N,q^n/(1-q^n-q^(2*n)-q^(3*n))))

%Y Cf. A007435 (g.f. Sum{n>=1} q^n/(1-q^n-q^(2*n))), A368689 (g.f. Sum_{n>=1} q^n/(1-q^(2*n)-q^(3*n))), A368688 (g.f. Sum_{n>=1} q^n/(1-q^n-q^(3*n))).

%K nonn

%O 1,2

%A _Joerg Arndt_, Jan 03 2024