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 1-3 of 3 results.

A202630 G.f.: exp( Sum_{n>=1} (3^n + A(x))^n * x^n/n ).

Original entry on oeis.org

1, 4, 62, 7646, 11346032, 173032723944, 25223251091617644, 34295314615208803660344, 429734276354140075492905291038, 49292144933883713910495181570024546094, 51546480948489890934875222750204184228031911158
Offset: 0

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Author

Paul D. Hanna, Dec 21 2011

Keywords

Examples

			G.f.: A(x) = 1 + 4*x + 62*x^2 + 7646*x^3 + 11346032*x^4 + 173032723944*x^5 +...
where
log(A(x)) = (3 + A(x))*x + (3^2 + A(x))^2*x^2/2 + (3^3 + A(x))^3*x^3/3 + (3^4 + A(x))^4*x^4/4 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x);for(i=1,n,A=exp(sum(m=1,n,(3^m+A+x*O(x^n))^m*x^m/m)));polcoeff(A,n)}

A185385 G.f. satisfies: A(x) = exp( Sum_{n>=1} (2*A(x) - (-1)^n)^n * x^n/n ).

Original entry on oeis.org

1, 3, 11, 61, 381, 2527, 17559, 126265, 931321, 7007035, 53568131, 414929621, 3249392917, 25684315319, 204645707183, 1641910625009, 13253684541553, 107561523423731, 877109999610107, 7183095973808493, 59053492869471661, 487189276030904207, 4032100262853037127
Offset: 0

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Author

Paul D. Hanna, Dec 22 2011

Keywords

Examples

			G.f.: A(x) = 1 + 3*x + 11*x^2 + 61*x^3 + 381*x^4 + 2527*x^5 + 17559*x^6 +...
where
log(A(x)) = (2*A(x) + 1)*x + (2*A(x) - 1)^2*x^2/2 + (2*A(x) + 1)^3*x^3/3 + (2*A(x) - 1)^4*x^4/4 +...
log(A(x)*(1-2*x*A(x))) = 1/(1 + 2*x*A(x))*x + 1/(1 - 2*x*A(x))^2*x^2/2 + 1/(1 + 2*x*A(x))^3*x^3/3 + 1/(1 - 2*x*A(x))^4*x^4/4 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x); for(i=1, n, A=exp(sum(m=1, n, (2*A-(-1)^m+x*O(x^n))^m*x^m/m))); polcoeff(A, n)}

Formula

G.f. satisfies: A(x) = 1/(1-2*x*A(x)) * exp( Sum_{n>=1} 1/(1 - (-1)^n*2*x*A(x))^n * x^n/n ).
G.f. satisfies: A(x) = sqrt( (1 - (2*A(x)+1)^2*x^2)/(1 - (2*A(x)-1)^2*x^2) ) / (1 - (2*A(x)+1)*x).
G.f. satisfies: 0 = -(1+x) - 2*x*A(x) + (1+x)*(1-x)^2*A(x)^2 - 2*x*(1-x)^2*A(x)^3 - 2^2*x^2*(1+x)*A(x)^4 + 2^3*x^3*A(x)^5.

A202669 G.f. satisfies: A(x) = exp( Sum_{n>=1} (A(x) + (-1)^n)^n * x^n/n ).

Original entry on oeis.org

1, 0, 2, 2, 12, 20, 96, 212, 898, 2354, 9266, 27070, 102094, 319930, 1177838, 3865762, 14050948, 47574460, 171886784, 594572676, 2143957648, 7528825924, 27156892364, 96412294088, 348314869652, 1246689890248, 4513958859208, 16257651642036, 59010423148052, 213586733348928
Offset: 0

Views

Author

Paul D. Hanna, Dec 22 2011

Keywords

Examples

			G.f.: A(x) = 1 + 2*x^2 + 2*x^3 + 12*x^4 + 20*x^5 + 96*x^6 + 212*x^7 +...
where
log(A(x)) = (A(x) - 1)*x + (A(x) + 1)^2*x^2/2 + (A(x) - 1)^3*x^3/3 + (A(x) + 1)^4*x^4/4 +...
log(A(x)*(1-x*A(x))) = -1/(1 + x*A(x))*x + 1/(1 - x*A(x))^2*x^2/2 - 1/(1 + x*A(x))^3*x^3/3 + 1/(1 - x*A(x))^4*x^4/4 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=1+x); for(i=1, n, A=exp(sum(m=1, n, (A+(-1)^m+x*O(x^n))^m*x^m/m))); polcoeff(A, n)}

Formula

G.f. satisfies: A(x) = 1/(1-x*A(x)) * exp( Sum_{n>=1} (-1)^n/(1 - (-1)^n*x*A(x))^n * x^n/n ).
G.f. satisfies: A(x) = sqrt( (1 - (A(x)-1)^2*x^2)/(1 - (A(x)+1)^2*x^2) ) / (1 - (A(x)-1)*x).
G.f. satisfies: 0 = -(1-x) - x*A(x) + (1-x)*(1+x)^2*A(x)^2 - x*(1+x)^2*A(x)^3 - x^2*(1-x)*A(x)^4 + x^3*A(x)^5.
Showing 1-3 of 3 results.