Expansion of g.f. Product_{k>=2} 1/(1-x^phi(k)).

Terms

a(0) =1a(1) =1a(2) =4a(3) =4a(4) =14a(5) =14a(6) =40a(7) =40a(8) =106a(9) =106a(10) =254a(11) =254a(12) =582a(13) =582a(14) =1256a(15) =1256a(16) =2620a(17) =2620a(18) =5256a(19) =5256a(20) =10266a(21) =10266a(22) =19482a(23) =19482a(24) =36204a(25) =36204a(26) =65792a(27) =65792a(28) =117496a(29) =117496