editing

approved

Unique sequence of numbers {1,2,3,4} where g.f. A(x) satisfies A(x) = B(B(B(B(x)))) (4th self-COMPOSE) such that B(x) is an integer sequence, series, with A(0) = 0.

proposed

editing

editing

proposed

Unique sequence of numbers {1,2,3,4} where g.f. A(x) satisfies A(x) = B(B(B(B(x)))) (4th self-COMPOSE) such that B(x) is an integer series, sequence, with A(0) = 0.

G.f.: A(x) = x + 4*x^2 + 4*x^3 + 2*x^4 + 4*x^5 + 2*x^6 + ...

B(x) = x + x^2 - 2*x^3 + 8*x^4 - 38*x^5 + 194*x^6 - 992*x^7 + ...

approved

editing

editing

approved

Unique sequence of numbers {1,2,3,4} where g.f. A(x) satisfies A(x) = B(B(B(B(x)))) (4-th 4th self-COMPOSE) such that B(x) is an integer series, with A(0) = 0.

approved

editing

_Paul D. Hanna (pauldhanna(AT)juno.com), _, Aug 27 2005

nonn,new

nonn

Paul D . Hanna (pauldhanna(AT)juno.com), Aug 27 2005

(PARI) {a(n, m=4)=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)))}

nonn,new

nonn

Unique sequence of numbers {1,2,3,4} where g.f. A(x) satisfies A(x) = B(B(B(B(x)))) (4-th self-COMPOSE) such that B(x) is an integer series, with A(0) = 0.

1, 4, 4, 2, 4, 2, 4, 4, 2, 4, 4, 2, 2, 4, 4, 2, 2, 4, 4, 3, 4, 3, 2, 4, 1, 2, 4, 2, 3, 1, 4, 2, 4, 3, 1, 4, 4, 4, 2, 2, 2, 3, 3, 2, 3, 2, 2, 4, 1, 4, 2, 2, 1, 4, 3, 3, 3, 1, 1, 3, 3, 4, 4, 3, 3, 3, 3, 1, 4, 4, 3, 2, 4, 2, 2, 2, 1, 3, 4, 2, 3, 3, 1, 4, 2, 3, 1, 1, 3, 3, 4, 2, 4, 3, 1, 4, 3, 2, 1, 1, 1, 2, 1, 4, 4

1,2

G.f.: A(x) = x + 4*x^2 + 4*x^3 + 2*x^4 + 4*x^5 + 2*x^6 +...

then A(x) = B(B(B(B(x)))) where

B(x) = x + x^2 - 2*x^3 + 8*x^4 - 38*x^5 + 194*x^6 - 992*x^7 +...

is the g.f. of A112109.

(PARI) {a(n, m=4)=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)))}

Cf. A112109, A112104-A112107, A112110-A112127.

nonn

Paul D Hanna (pauldhanna(AT)juno.com), Aug 27 2005

approved