cp's OEIS Frontend

A206720 G.f.: A(x) = x/(1-x) o x/(1-x^3) o x/(1-x^5) o x/(1-x^7) o..., a composition of functions x/(1-x^(2*n-1)) for n=1,2,3,...

%I A206720 #8 Mar 30 2012 18:37:35
%S A206720 1,1,1,2,3,5,8,13,23,38,63,105,178,300,501,849,1431,2405,4044,6812,
%T A206720 11491,19361,32621,54946,92646,156118,262964,443200,746933,1258840,
%U A206720 2121343,3575153,6025323,10154336,17112673,28839762,48605300,81913614,138049346,232655873
%N A206720 G.f.: A(x) = x/(1-x) o x/(1-x^3) o x/(1-x^5) o x/(1-x^7) o..., a composition of functions x/(1-x^(2*n-1)) for n=1,2,3,...
%C A206720 Compositional transpose of A206721.
%e A206720 G.f.: A(x) = x + x^2 + x^3 + 2*x^4 + 3*x^5 + 5*x^6 + 8*x^7 + 13*x^8 +...
%e A206720 where A(x) is the limit of composition of functions x/(1-x^(2*n-1)):
%e A206720 F_1(x) = x/(1-x)
%e A206720 F_2(x) = F_1(x/(1-x^3)) = x + x^2 + x^3 + 2*x^4 + 3*x^5 + 4*x^6 + 6*x^7 +...
%e A206720 F_3(x) = F_2(x/(1-x^5)) = x + x^2 + x^3 + 2*x^4 + 3*x^5 + 5*x^6 + 8*x^7 +...
%e A206720 F_4(x) = x/(1-x) o x/(1-x^3) o x/(1-x^5) o x/(1-x^7); ...
%o A206720 (PARI) {a(n)=local(A=x+x*O(x^n)); if(n<=0, 0, for(i=1, n, A=A/(1-A^(2*(n-i)+1))); polcoeff(A, n))}
%o A206720 for(n=1,45,print1(a(n),", "))
%Y A206720 Cf. A206721, A136750.
%K A206720 nonn
%O A206720 1,4
%A A206720 _Paul D. Hanna_, Feb 11 2012