A112114 Unique sequence of numbers {1,2,3,...,7} where g.f. A(x) satisfies A(x) = B(B(B(..(B(x))..))) (7th self-COMPOSE) such that B(x) is an integer series, with A(0) = 0.
1, 7, 7, 7, 7, 7, 7, 7, 6, 6, 6, 6, 6, 6, 5, 3, 3, 3, 3, 3, 2, 2, 1, 1, 1, 1, 7, 4, 7, 4, 4, 4, 3, 2, 5, 3, 1, 1, 7, 5, 2, 4, 2, 2, 1, 2, 6, 5, 1, 5, 7, 7, 7, 7, 5, 6, 5, 6, 4, 1, 6, 1, 2, 7, 1, 5, 3, 7, 2, 4, 4, 4, 3, 2, 4, 5, 7, 7, 3, 1, 2, 3, 5, 5, 6, 4, 7, 6, 1, 6, 5, 2, 1, 1, 6, 1, 4, 3, 1, 2, 3, 3, 3, 7, 1
Offset: 1
Keywords
Examples
G.f.: A(x) = x + 7*x^2 + 7*x^3 + 7*x^4 + 7*x^5 + 7*x^6 + 7*x^7 + ... then A(x) = B(B(B(B(B(B(B(x))))))) where B(x) = x + x^2 - 5*x^3 + 43*x^4 - 443*x^5 + 4957*x^6 - 57281*x^7 + ... is the g.f. of A112115.
Programs
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PARI
{a(n,m=7)=local(F=x+x^2+x*O(x^n),G);if(n<1,0, for(k=3,n, G=F+x*O(x^k);for(i=1,m-1,G=subst(F,x,G)); F=F-((polcoeff(G,k)-1)\m)*x^k); G=F+x*O(x^n);for(i=1,m-1,G=subst(F,x,G)); return(polcoeff(G,n,x)))}