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 1-5 of 5 results.

A258880 E.g.f. satisfies: A(x) = Integral 1 + A(x)^3 dx.

Original entry on oeis.org

1, 6, 540, 184680, 157600080, 270419925600, 816984611467200, 3971317527112003200, 29097143353353192480000, 305823675529741700675520000, 4435486895868663971869188480000, 86036822683997062842122964537600000, 2175352015640142857526698650779456000000
Offset: 0

Views

Author

Paul D. Hanna, Jun 13 2015

Keywords

Comments

Note: Sum_{n>=0} (-1)^n*x^(3*n+1)/(3*n+1) = log( (1+x)/(1-x^3)^(1/3) )/2 + Pi*sqrt(3)/18 - atan( (1-2*x)*sqrt(3)/3 )*sqrt(3)/3.

Examples

			E.g.f.: A(x) = x + 6*x^4/4! + 540*x^7/7! + 184680*x^10/10! + 157600080*x^13/13! + 270419925600*x^16/16! +...
where Series_Reversion(A(x)) =  x - x^4/4 + x^7/7 - x^10/10 + x^13/13 - x^16/16 +...
		

Crossrefs

Programs

  • Mathematica
    terms = 13;
    A[_] = 0;
    Do[A[x_] = Integrate[1 + A[x]^3, x] + O[x]^k // Normal, {k, 1, 3 terms}];
    DeleteCases[CoefficientList[A[x], x] Range[0, 3 terms - 2]!, 0] (* Jean-François Alcover, Jul 25 2018 *)
  • PARI
    {a(n) = local(A=x); A = serreverse( sum(m=0,n, (-1)^m * x^(3*m+1)/(3*m+1) ) +O(x^(3*n+2)) ); (3*n+1)!*polcoeff(A,3*n+1)}
    for(n=0,20,print1(a(n),", "))
    
  • PARI
    /* E.g.f. A(x) = Integral 1 + A(x)^3 dx.: */
    {a(n) = local(A=x); for(i=1,n+1, A = intformal( 1 + A^3 + O(x^(3*n+2)) )); (3*n+1)!*polcoeff(A,3*n+1)}
    for(n=0,20,print1(a(n),", "))

Formula

E.g.f.: Series_Reversion( Integral 1/(1+x^3) dx ).
E.g.f.: Series_Reversion( Sum_{n>=0} (-1)^n * x^(3*n+1)/(3*n+1) ).
a(n) ~ 3^(15*n/2 + 17/4) * n^(3*n+1) / (exp(3*n) * (2*Pi)^(3*n+3/2)). - Vaclav Kotesovec, Jun 15 2015

A258901 E.g.f. satisfies: A(x) = Integral 1 + A(x)^4 dx.

Original entry on oeis.org

1, 24, 32256, 285272064, 8967114326016, 735868743566229504, 130778914961055994085376, 44390350317502907443360825344, 26290393222157669992962395876622336, 25377887922329300948014930852183837507584, 37855568618678541873143615775486954119570128896
Offset: 0

Views

Author

Paul D. Hanna, Jun 14 2015

Keywords

Examples

			E.g.f.: A(x) = x + 24*x^5/5! + 32256*x^9/9! + 285272064*x^13/13! + 8967114326016*x^17/17! + 735868743566229504*x^21/21! +...
where Series_Reversion(A(x)) = x - x^5/5 + x^9/9 - x^13/13 + x^17/17 +...
Also, A(x) = S(x)/C(x) where
S(x) = x - 6*x^5/5! - 1764*x^9/9! - 7700616*x^13/13! - 147910405104*x^17/17! - 8310698364852576*x^21/21! +...+ A258900(n)*x^(4*n+1)/(4*n+1)! +...
C(x) = 1 - 6*x^4/4! - 1764*x^8/8! - 7700616*x^12/12! - 147910405104*x^16/16! - 8310698364852576*x^20/20! +...+ A258900(n)*x^(4*n)/(4*n)! +...
such that C(x)^4 + S(x)^4 = 1.
		

Crossrefs

Programs

  • Mathematica
    nmax=20; Table[CoefficientList[InverseSeries[Series[Integrate[1/(1+x^4),x],{x,0,4*nmax+1}],x],x][[4*n-2]] * (4*n-3)!, {n,1,nmax+1}] (* Vaclav Kotesovec, Jun 18 2015 *)
  • PARI
    /* E.g.f. Series_Reversion( Integral 1/(1+x^4) dx ): */
    {a(n) = local(A=x); A = serreverse( intformal( 1/(1 + x^4 + O(x^(4*n+2))) ) ); (4*n+1)!*polcoeff(A,4*n+1)}
    for(n=0,20,print1(a(n),", "))
    
  • PARI
    /* E.g.f. A(x) = Integral 1 + A(x)^4 dx.: */
    {a(n) = local(A=x); for(i=1,n+1, A = intformal( 1 + A^4 + O(x^(4*n+2)) )); (4*n+1)!*polcoeff(A,4*n+1)}
    for(n=0,20,print1(a(n),", "))

Formula

E.g.f. A(x) satisfies:
(1) A(x) = Series_Reversion( Integral 1/(1+x^4) dx ).
(2) A(x) = sqrt( tan( 2 * Integral A(x) dx ) ).
Let C(x) = S'(x) such that S(x) = Series_Reversion( Integral 1/(1-x^4)^(1/4) dx ) is the e.g.f. of A258900, then e.g.f. A(x) of this sequence satisfies:
(3) A(x) = S(x)/C(x),
(4) A(x) = Integral 1/C(x)^4 dx,
(5) A(x)^2 = S(x)^2/C(x)^2 = tan( 2 * Integral S(x)/C(x) dx ).
a(n) ~ 2^(6*n + 14/3) * (4*n)! * n^(1/3) / (3^(1/3) * Gamma(1/3) * Pi^(4*n + 4/3)). - Vaclav Kotesovec, Jun 18 2015

A258927 E.g.f. satisfies: A(x) = Integral 1 + A(x)^6 dx.

Original entry on oeis.org

1, 720, 410572800, 4492717498368000, 348990783113936240640000, 118162808964225967251573964800000, 130226468530398571130647349959852032000000, 384446125794905598149974467971605129718661120000000, 2644398446216951886577241780697447635225293650237849600000000
Offset: 0

Views

Author

Paul D. Hanna, Jun 15 2015

Keywords

Comments

From Vaclav Kotesovec, Jun 17 2015: (Start)
In general, for k>2, if e.g.f. satisfies A(x) = Integral 1 + A(x)^k dx, then a(n) ~ k^(k/(k-1)) * n^(1/(k-1)) * (k*n)! * (k*sin(Pi/k)/Pi)^(k*n + k/(k-1)) / ((k-1)^(1/(k-1)) * Gamma(1/(k-1))).
(End)

Examples

			E.g.f.: A(x) = x + 720*x^7/7! + 410572800*x^13/13! + 4492717498368000*x^19/19! +...
where Series_Reversion(A(x)) = x - x^7/7 + x^13/13 - x^19/19 + x^25/25 +...
Also, A(x) = S(x)/C(x) where
S(x) = x - 120*x^7/7! - 21859200*x^13/13! - 131273353728000*x^19/19! +...+ A258926(n)*x^(6*n+1)/(6*n+1)! +...
C(x) = 1 - 120*x^6/6! - 21859200*x^12/12! - 131273353728000*x^18/18! +...+ A258926(n)*x^(6*n)/(6*n)! +...
such that C(x)^6 + S(x)^6 = 1.
		

Crossrefs

Cf. A000182(n-1) (k=2), A258880 (k=3), A258901 (k=4), A258925 (k=5), A259112 (k=7), A259113 (k=8), A258926, A258994.

Programs

  • PARI
    /* E.g.f. Series_Reversion( Integral 1/(1+x^6) dx ): */
    {a(n) = local(A=x); A = serreverse( intformal( 1/(1 + x^6 + O(x^(6*n+2))) ) ); (6*n+1)!*polcoeff(A, 6*n+1)}
    for(n=0, 20, print1(a(n), ", "))
    
  • PARI
    /* E.g.f. A(x) = Integral 1 + A(x)^6 dx.: */
    {a(n) = local(A=x); for(i=1, n+1, A = intformal( 1 + A^6 + O(x^(6*n+2)) )); (6*n+1)!*polcoeff(A, 6*n+1)}
    for(n=0, 20, print1(a(n), ", "))

Formula

E.g.f. A(x) satisfies:
(1) A(x) = Series_Reversion( Integral 1/(1+x^6) dx ).
(2) A(x)^3 = tan( 3 * Integral A(x)^2 dx ).
Let C(x) = S'(x) such that S(x) = Series_Reversion( Integral 1/(1-x^6)^(1/6) dx ) is the e.g.f. of A258926, then e.g.f. A(x) of this sequence satisfies:
(3) A(x) = S(x)/C(x),
(4) A(x) = Integral 1/C(x)^6 dx,
(5) A(x)^3 = S(x)^3/C(x)^3 = tan( 3 * Integral S(x)^2/C(x)^2 dx ).
a(n) ~ 2^(6/5) * 3^(6*n+12/5) * (6*n)! * n^(1/5) / (5^(1/5) * Gamma(1/5) * Pi^(6*n+6/5)). - Vaclav Kotesovec, Jun 18 2015

A258925 E.g.f. satisfies: A(x) = Integral 1 + A(x)^5 dx.

Original entry on oeis.org

1, 120, 3024000, 858574080000, 1226178516326400000, 5912338932461445120000000, 75732595735526211882516480000000, 2195068320271703663798288449536000000000, 128322069958974226301129597680106864640000000000
Offset: 0

Views

Author

Paul D. Hanna, Jun 15 2015

Keywords

Examples

			E.g.f.: A(x) = x + 120*x^6/6! + 3024000*x^11/11! + 858574080000*x^16/16! +...
where Series_Reversion(A(x)) = x - x^6/6 + x^11/11 - x^16/16 + x^21/21 +...
Also, A(x) = S(x)/C(x) where
S(x) = x - 24*x^6/6! - 169344*x^11/11! - 25255286784*x^16/16! - 23089632627769344*x^21/21! +...+ A258924(n)*x^(5*n+1)/(5*n+1)! +...
C(x) = 1 - 24*x^5/5! - 169344*x^10/10! - 25255286784*x^15/15! - 23089632627769344*x^20/20! +...+ A258924(n)*x^(5*n)/(5*n)! +...
such that C(x)^5 + S(x)^5 = 1.
		

Crossrefs

Programs

  • PARI
    /* E.g.f. Series_Reversion( Integral 1/(1+x^5) dx ): */
    {a(n) = local(A=x); A = serreverse( intformal( 1/(1 + x^5 + O(x^(5*n+2))) ) ); (5*n+1)!*polcoeff(A, 5*n+1)}
    for(n=0, 20, print1(a(n), ", "))
    
  • PARI
    /* E.g.f. A(x) = Integral 1 + A(x)^5 dx.: */
    {a(n) = local(A=x); for(i=1, n+1, A = intformal( 1 + A^5 + O(x^(5*n+2)) )); (5*n+1)!*polcoeff(A, 5*n+1)}
    for(n=0, 20, print1(a(n), ", "))

Formula

E.g.f. A(x) satisfies:
(1) A(x) = Series_Reversion( Integral 1/(1+x^5) dx ).
Let C(x) = S'(x) such that S(x) = Series_Reversion( Integral 1/(1-x^5)^(1/5) dx ) is the e.g.f. of A258924, then e.g.f. A(x) of this sequence satisfies:
(2) A(x) = S(x)/C(x),
(3) A(x) = Integral 1/C(x)^5 dx.
From Vaclav Kotesovec, Jun 18 2015: (Start)
a(n) ~ 5^(5*n+5/2) * ((5-sqrt(5))/8)^(5*n/2+5/8) * (5*n)! * n^(1/4) / (sqrt(2) * Gamma(1/4) * Pi^(5*n+5/4)).
a(n) ~ 5^(5*n+5/2) * sin(Pi/5)^(5*n+5/4) * (5*n)! * n^(1/4) / (sqrt(2) * Gamma(1/4) * Pi^(5*n+5/4)).
(End)

A259113 E.g.f. satisfies: A(x) = Integral 1 + A(x)^8 dx.

Original entry on oeis.org

1, 40320, 18598035456000, 474009962689446543360000, 170149872975531014630262649651200000, 442695618409212548301531680485487369256960000000, 5620045472937667963281036681944526735620775198955929600000000
Offset: 0

Views

Author

Vaclav Kotesovec, Jun 18 2015

Keywords

Comments

In general, for k>2, if e.g.f. satisfies A(x) = Integral 1 + A(x)^k dx, then a(n) ~ k^(k/(k-1)) * n^(1/(k-1)) * (k*n)! * (k*sin(Pi/k)/Pi)^(k*n + k/(k-1)) / ((k-1)^(1/(k-1)) * Gamma(1/(k-1))).

Crossrefs

Cf. A258880 (k=3), A258901 (k=4), A258925 (k=5), A258927 (k=6), A259112 (k=7).

Programs

  • PARI
    {a(n) = local(A=x); A = serreverse( intformal( 1/(1 + x^8 + O(x^(8*n+2))) ) ); (8*n+1)!*polcoeff(A, 8*n+1)}
    for(n=0, 20, print1(a(n), ", ")) \\ after Paul D. Hanna

Formula

a(n) ~ 2^(24*n+48/7) * n^(1/7) * (sin(Pi/8)/Pi)^(8*n+8/7) * (8*n)! / (7^(1/7) * GAMMA(1/7)).
a(n) ~ 2^(16*n+40/7) * (2-sqrt(2))^(4*n+4/7) * n^(1/7) * (8*n)! / (7^(1/7) * GAMMA(1/7) * Pi^(8*n+8/7)).
Showing 1-5 of 5 results.