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.

A301363 G.f. A(x) satisfies: A(x) = 1/(1 - x*A(x)/(1 - 2*x*A(x)/(1 - 3*x*A(x)/(1 - 4*x*A(x)/(1 - ...))))), a continued fraction.

Original entry on oeis.org

1, 1, 4, 25, 202, 1966, 22306, 289969, 4272934, 70792318, 1308702592, 26791202362, 602762346088, 14795609964448, 393567982759966, 11276489767853569, 346158428070229414, 11331678979354212886, 393967314482937530248, 14495027742943618066030, 562600190990455844759356
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 19 2018

Keywords

Examples

			G.f. A(x) = 1 + x + 4*x^2 + 25*x^3 + 202*x^4 + 1966*x^5 + 22306*x^6 + 289969*x^7 + 4272934*x^8 + ...
The g.f. also satisfies:
A(x) = 1 + x*A(x) + 3*x^2*A(x) + 15*x^3*A(x)^3 + 105*x^4*A(x)^4 + 945*x^5*A(x)^5 + 10395*x^6*A(x)^6 + ... + (2*n)!/(n!*2^n) * x^n * A(x)^n + ...
		

Crossrefs

Programs

  • PARI
    /* Continued Fraction */
    {a(n) = my(A=1, CF = 1+x +x*O(x^n)); for(i=1,n, A=CF; for(k=0, n, CF = 1/(1 - (n-k+1)*x*A*CF ) )); polcoeff(CF, n)}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* Differential Equation */
    {a(n) = my(A=1); for(i=0,n, A = 1 + x*(x*A^3)'/(x*A +x^2*O(x^n))'); polcoeff(A,n)}
    for(n=0, 30, print1(a(n),", "))

Formula

G.f. A(x) satisfies: A(x) = 1 + x * (x*A(x)^3)' / (x*A(x))'. - Paul D. Hanna, Apr 01 2018
G.f. A(x) satisfies: A(x) = (1/x)*Series_Reversion(x/F(x)) where F(x) = A(x/F(x)) = Sum_{n>=0} (2*n)!/(n!*2^n)*x^n is an o.g.f. of A001147. - Paul D. Hanna, Apr 05 2018
G.f. A(x) satisfies: A(x) = Sum_{n>=0} (2*n)!/(n!*2^n) * x^n * A(x)^n. - Paul D. Hanna, Apr 09 2018
a(n) ~ 2^(n + 1/2) * n^n / exp(n - 1/2). - Vaclav Kotesovec, Jun 18 2019

A302100 G.f. A(x) satisfies: A(x) = Sum_{n>=0} x^n * A(x)^n * Product_{k=0..n-1} (3*k + 1).

Original entry on oeis.org

1, 1, 5, 41, 449, 6081, 98133, 1846377, 39888353, 977117825, 26839621829, 818332799593, 27443807417569, 1004188344449473, 39809506543659477, 1699473112658002089, 77716022374143303489, 3789578550994707778305, 196255782523222432943109, 10756748528551996006448553, 622036345094017435642828161, 37846075344692579622469742529
Offset: 0

Views

Author

Paul D. Hanna, Apr 09 2018

Keywords

Examples

			G.f.: A(x) = 1 + x + 5*x^2 + 41*x^3 + 449*x^4 + 6081*x^5 + 98133*x^6 + 1846377*x^7 + 39888353*x^8 + 977117825*x^9 + 26839621829*x^10 + ...
such that
A(x) = 1 + x*A(x) + 4*x^2*A(x)^2 + 28*x^3*A(x)^3 + 280*x^4*A(x)^4 + 3640*x^5*A(x)^5 + 58240*x^6*A(x)^6 + ... + x^n * A(x)^n * Product_{k=0..n-1} (3*k + 1) + ...
		

Crossrefs

Programs

  • PARI
    /* Series Reversion of Triple Factorials g.f.: */
    {a(n) = polcoeff((1/x) * serreverse(x/sum(m=0, n, x^m * prod(k=0,m-1,3*k + 1)) +x^2*O(x^n)), n)}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* Differential Equation: */
    {a(n) = my(A=1); for(i=0, n, A = 1 + x*A^2*(A + 4*x*A')/(x*A +x^2*O(x^n))'); polcoeff(A, n)}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* Continued fraction: */
    {a(n) = my(A=1, CF = 1+x +x*O(x^n)); for(i=1, n, A=CF; for(k=0, n, CF = 1/(1 - floor(3*(n-k+1)/2)*x*A*CF ) )); polcoeff(CF, n)}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) satisfies:
(1) A(x) = Sum_{n>=0} x^n * A(x)^n * Product_{k=0..n-1} (3*k + 1).
(2) A(x) = (1/x)*Series_Reversion( x/F(x) ), where F(x) = Sum_{n>=0} A007559(n)*x^n, the o.g.f. of the triple factorials.
(3) A(x) = 1 + x*A(x)^2 * (A(x) + 4*x*A'(x)) / (A(x) + x*A'(x)).
(4) A(x) = 1/(1 - x*A(x)/(1 - 3*x*A(x)/(1 - 4*x*A(x)/(1 - 6*x*A(x)/(1 - 7*x*A(x)/(1 - 9*x*A(x)/(1 - 10*x*A(x)/(1 - ...)))))))), a continued fraction.
a(n) ~ sqrt(2*Pi) * 3^n * n^(n - 1/6) / (Gamma(1/3) * exp(n - 1/3)). - Vaclav Kotesovec, Jun 18 2019

A302565 G.f. A(x) satisfies: A(x) = Sum_{n>=0} x^n * A(x)^n * Product_{k=0..n-1} (5*k + 1).

Original entry on oeis.org

1, 1, 7, 85, 1429, 30517, 792007, 24293389, 862902745, 34918162057, 1587910815271, 80217252865861, 4457823231346717, 270261899977497325, 17749585402744292215, 1255201826997862952845, 95083758340337074058545, 7680863233559647281837265, 659040900304099125516970375, 59855299015030039092312638965
Offset: 0

Views

Author

Paul D. Hanna, Apr 09 2018

Keywords

Examples

			G.f.: A(x) = 1 + x + 7*x^2 + 85*x^3 + 1429*x^4 + 30517*x^5 + 792007*x^6 + 24293389*x^7 + 862902745*x^8 + 34918162057*x^9 + ...
such that
A(x) = 1 + x*A(x) + 6*x^2*A(x)^2 + 66*x^3*A(x)^3 + 1056*x^4*A(x)^4 + 22176*x^5*A(x)^5 + ... + x^n*A(x)^n * Product_{k=0..n-1} (5*k + 1) + ...
		

Crossrefs

Programs

  • PARI
    /* Series Reversion of Quintuple Factorials g.f.: */
    {a(n) = polcoeff((1/x) * serreverse(x/sum(m=0, n, x^m * prod(k=0, m-1, 5*k + 1)) +x^2*O(x^n)), n)}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* Differential Equation: */
    {a(n) = my(A=1); for(i=0, n, A = 1 + x*A^2*(A + 6*x*A')/(x*A +x^2*O(x^n))'); polcoeff(A, n)}
    for(n=0, 30, print1(a(n), ", "))
    
  • PARI
    /* Continued fraction: */
    {a(n) = my(A=1, CF = 1+x +x*O(x^n)); for(i=1, n, A=CF; for(k=0, n, CF = 1/(1 - floor(5*floor(3*(n-k+1)/2)/3)*x*A*CF ) )); polcoeff(CF, n)}
    for(n=0, 30, print1(a(n), ", "))

Formula

G.f. A(x) satisfies:
(1) A(x) = Sum_{n>=0} x^n * A(x)^n * Product_{k=0..n-1} (5*k + 1).
(2) A(x) = (1/x)*Series_Reversion( x/F(x) ), where F(x) = Sum_{n>=0} A008548(n)*x^n, the o.g.f. of the quintuple factorials.
(3) A(x) = 1 + x*A(x)^2 * (A(x) + 6*x*A'(x)) / (A(x) + x*A'(x)).
(4) A(x) = 1/(1 - x*A(x)/(1 - 5*x*A(x)/(1 - 6*x*A(x)/(1 - 10*x*A(x)/(1 - 11*x*A(x)/(1 - 15*x*A(x)/(1 - 16*x*A(x)/(1 - ...)))))))), a continued fraction.
a(n) ~ sqrt(2*Pi) * 5^n * n^(n - 3/10) / (Gamma(1/5) * exp(n - 1/5)). - Vaclav Kotesovec, Jun 18 2019
Showing 1-3 of 3 results.