cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A219260 G.f. satisfies: A(x) = exp(Sum_{n>=1} x^n*A(x)^n/n * Product_{k>=1} (1 + x^(n*k)*A(x^k)^n)).

Original entry on oeis.org

1, 1, 3, 10, 37, 143, 576, 2393, 10178, 44133, 194341, 866867, 3908454, 17784385, 81562890, 376637216, 1749704080, 8171760933, 38346326963, 180707395127, 854850922373, 4057990958069, 19324260613400, 92288612451684, 441919933724974, 2121281845071105, 10205443975074195
Offset: 0

Views

Author

Paul D. Hanna, Nov 16 2012

Keywords

Comments

Compare to the dual g.f. G(x) of A219261:
G(x) = exp(Sum_{n>=1} x^n*G(x^n)/n * Product_{k>=1} (1+x^(n*k)*G(x^n)^k)).

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 10*x^3 + 37*x^4 + 143*x^5 + 576*x^6 + 2393*x^7 +...
where
log(A(x)) = x*A(x)/1*((1+x*A(x))*(1+x^2*A(x^2))*(1+x^3*A(x^3))*...) +
x^2*A(x)^2/2*((1+x^2*A(x)^2)*(1+x^4*A(x^2)^2)*(1+x^6*A(x^3)^2)*...) +
x^3*A(x)^3/3*((1+x^3*A(x)^3)*(1+x^6*A(x^2)^3)*(1+x^9*A(x^3)^3)*...) +
x^4*A(x)^4/4*((1+x^4*A(x)^4)*(1+x^8*A(x^2)^4)*(1+x^12*A(x^3)^4)*...) +...
Explicitly,
log(A(x)) = x + 5*x^2/2 + 22*x^3/3 + 101*x^4/4 + 461*x^5/5 + 2144*x^6/6 + 10109*x^7/7 + 48117*x^8/8 + 230998*x^9/9 + 1115875*x^10/10 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x); for(i=1, n, A=exp(sum(m=1, n, x^m*A^m/m*prod(k=1, n\m+1, 1+x^(m*k)*subst(A^m, x, x^k +x*O(x^n)))))); polcoeff(A, n)}
    for(n=0, 30, print1(a(n), ", "))

A219263 G.f. satisfies: A(x) = exp( Sum_{n>=1} x^n*A(x^n)/n / Product_{k>=1} (1 - x^(n*k)*A(x^n)^k) ).

Original entry on oeis.org

1, 1, 3, 10, 39, 159, 693, 3101, 14292, 67116, 320448, 1549834, 7579037, 37406737, 186102602, 932294987, 4698796087, 23809155711, 121219100012, 619800529792, 3181291257740, 16385813881342, 84666104373097, 438742341955132, 2279628504172080, 11873579440176774, 61984238371422197
Offset: 0

Views

Author

Paul D. Hanna, Nov 16 2012

Keywords

Comments

Compare to the dual g.f. G(x) of A219262:
G(x) = exp( Sum_{n>=1} x^n*G(x)^n/n / Product_{k>=1} (1 - x^(n*k)*G(x^k)^n) ).

Examples

			G.f.: A(x) = 1 + x + 3*x^2 + 10*x^3 + 39*x^4 + 159*x^5 + 693*x^6 + 3101*x^7 +...
where
log(A(x)) = x*A(x)/1/((1-x*A(x))*(1-x^2*A(x)^2)*(1-x^3*A(x)^3)*...) +
x^2*A(x^2)/2/((1-x^2*A(x^2))*(1-x^4*A(x^2)^2)*(1-x^6*A(x^2)^3)*...) +
x^3*A(x^3)/3/((1-x^3*A(x^3))*(1-x^6*A(x^3)^2)*(1-x^9*A(x^3)^3)*...) +
x^4*A(x^4)/4/((1-x^4*A(x^4))*(1-x^8*A(x^4)^2)*(1-x^12*A(x^4)^3)*...) +...
Explicitly,
log(A(x)) = x + 5*x^2/2 + 22*x^3/3 + 109*x^4/4 + 531*x^5/5 + 2726*x^6/6 + 13952*x^7/7 + 72581*x^8/8 + 379264*x^9/9 + 1994875*x^10/10 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x); for(i=1, n, A=exp(sum(m=1, n, x^m*subst(A, x, x^m +x*O(x^n))/m/prod(k=1, n\m+1, 1-x^(m*k)*subst(A^k, x, x^m +x*O(x^n)))))); polcoeff(A, n)}
    for(n=0, 30, print1(a(n), ", "))
Showing 1-2 of 2 results.