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 1-6 of 6 results.

A136750 G.f.: A(x) = x/(1-x) o x/(1-x^2) o x/(1-x^3) o x/(1-x^4) o..., composition of functions x/(1-x^n) for n = ...,3,2,1.

Original entry on oeis.org

1, 1, 2, 4, 8, 17, 35, 74, 155, 329, 692, 1464, 3098, 6553, 13873, 29361, 62165, 131638, 278787, 590357, 1250337, 2648108, 5608735, 11879607, 25161906, 53295451, 112886028, 239108343, 506466366, 1072776347, 2272316123, 4813150684
Offset: 0

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Author

Paul D. Hanna, Jan 21 2008

Keywords

Comments

The composition transpose of A136751.

Examples

			G.f.: A(x) is the limit of composition of functions x/(1-x^n):
F_1(x) = x/(1-x)
F_2(x) = F_1(x/(1-x^2)) = x + x^2 + 2x^3 + 3x^4 + 5x^5 + 8*x^6 + 13x^7 +...
F_3(x) = F_2(x/(1-x^3)) = x + x^2 + 2x^3 + 4x^4 + 7x^5 + 14x^6 + 26x^7 +...
F_4(x) = F_3(x/(1-x^4)) = x + x^2 + 2x^3 + 4x^4 + 8x^5 + 16x^6 + 32x^7 +...
F_5(x) = F_4(x/(1-x^5)) = x + x^2 + 2x^3 + 4x^4 + 8x^5 + 17x^6 + 34x^7 +...
F_6(x) = x/(1-x) o x/(1-x^2) o x/(1-x^3) o x/(1-x^4) o x/(1-x^5) o x/(1-x^6) =
x + x^2 + 2*x^3 + 4*x^4 + 8*x^5 + 17*x^6 + 35*x^7 + 73*x^8 + 152*x^9 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=x+x*O(x^n));if(n<=0,0,for(i=1,n,A=A/(1-A^(n-i+1)));polcoeff(A,n))}
    for(n=1,30,print1(a(n),", "))

A277180 E.g.f.: A(x) = ... x*exp(x^4) o x*exp(x^3) o x*exp(x^2) o x*exp(x), the composition of functions x*exp(x^n) for n = 1,2,3,...

Original entry on oeis.org

1, 2, 9, 100, 1205, 18006, 350077, 8088536, 211371561, 6176234890, 200898827921, 7219180413732, 284177412817597, 12162803253287246, 562046000617917285, 27867599169654763696, 1475047571057004959057, 83000104748219010488850, 4947512767013757600177049, 311464596400042198210554620, 20652342444419128752639269541, 1438800618216725748602640496342
Offset: 1

Views

Author

Paul D. Hanna, Oct 04 2016

Keywords

Comments

The compositional transpose of functions x*exp(x^n) yields the e.g.f. of A277181.

Examples

			E.g.f.: A(x) = x + 2*x^2/2! + 9*x^3/3! + 100*x^4/4! + 1205*x^5/5! + 18006*x^6/6! + 350077*x^7/7! + 8088536*x^8/8! + 211371561*x^9/9! + 6176234890*x^10/10! + 200898827921*x^11/11! + 7219180413732*x^12/12! +...
such that A(x) is the limit of composition of functions x*exp(x^n):
A(x) = ... o x*exp(x^5) o x*exp(x^4) o x*exp(x^3) o x*exp(x^2) o x*exp(x)
working from right to left.
Illustration of generating method.
Start with F_0(x) = x and then continue as follows.
F_1(x) = x*exp(x),
F_2(x) = F_1(x) * exp( F_1(x)^2 ),
F_3(x) = F_2(x) * exp( F_2(x)^3 ),
F_4(x) = F_3(x) * exp( F_3(x)^4 ),
...
F_{n+1}(x) = F_{n}(x) * exp( F_{n}(x)^(n+1) )
...
the limit of which equals the e.g.f. A(x).
The above series begin:
F_1(x) = x + 2*x^2/2! + 3*x^3/3! + 4*x^4/4! + 5*x^5/5! + 6*x^6/6! +...
F_2(x) = x + 2*x^2/2! + 9*x^3/3! + 76*x^4/4! + 605*x^5/5! + 5046*x^6/6! +...
F_3(x) = x + 2*x^2/2! + 9*x^3/3! + 100*x^4/4! + 1085*x^5/5! + 13686*x^6/6! +...
F_4(x) = x + 2*x^2/2! + 9*x^3/3! + 100*x^4/4! + 1205*x^5/5! + 17286*x^6/6! +...
...
RELATED SERIES.
The logarithm of A(x)/x begins:
log(A(x)/x) = x + 2*x^2/2! + 18*x^3/3! + 144*x^4/4! + 1660*x^5/5! + 27480*x^6/6! + 548394*x^7/7! + 12402992*x^8/8! + 316789848*x^9/9! + 9158652720*x^10/10! + 296955697390*x^11/11! + 10666960742328*x^12/12! +...+ A277182(n)*x^n/n! +...
The series reversion of the e.g.f. begins:
Series_Reversion(A(x)) = x - 2*x^2/2! + 3*x^3/3! - 40*x^4/4! + 505*x^5/5! - 4776*x^6/6! + 53179*x^7/7! - 1065296*x^8/8! + 25478289*x^9/9! - 480072880*x^10/10! + 9400182451*x^11/11! - 300620572968*x^12/12! +...
		

Crossrefs

Cf. A277182 (log A(x)/x), A277181, A136751.
Cf. A278332.

Programs

  • PARI
    {a(n) = my(A=x +x*O(x^n)); if(n<=0, 0, for(i=1, n, A = A*exp(A^i)); n!*polcoeff(A, n))}
    for(n=1,30,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A=x +x*O(x^n)); if(n<=0, 0, for(i=1, n, A = subst(A,x, x*exp(x^(n-i+1) +x*O(x^n))))); n!*polcoeff(A, n)}
    for(n=1,30,print1(a(n),", "))

Formula

E.g.f. A(x) satisfies: Series_Reversion(A(x)) = LambertW(x) o (LambertW(2*x^2)/2)^(1/2) o (LambertW(3*x^3)/3)^(1/3) o (LambertW(4*x^4)/4)^(1/4) o ..., the composition of functions (LambertW(n*x^n)/n)^(1/n) for n = ...,3,2,1.

A277181 E.g.f.: A(x) = x*exp(x) o x*exp(x^2) o x*exp(x^3) o x*exp(x^4) o ..., the composition of functions x*exp(x^n) for n=...,3,2,1.

Original entry on oeis.org

1, 2, 9, 76, 605, 7326, 97237, 1414904, 24130521, 467773210, 9636459041, 215484787332, 5351427245749, 141098897750006, 3995090542811565, 120415709525270896, 3833710980240095537, 130061101059127375794, 4649348119132468282681, 174231442774945244111420, 6859230825811289134828941, 282654139723294546295799502, 12162998707984268597918477189, 546138551651775603897277518696
Offset: 1

Views

Author

Paul D. Hanna, Oct 04 2016

Keywords

Comments

The compositional transpose of functions x*exp(x^n) yields the e.g.f. of A277180.

Examples

			E.g.f.: A(x) = x + 2*x^2/2! + 9*x^3/3! + 76*x^4/4! + 605*x^5/5! + 7326*x^6/6! + 97237*x^7/7! + 1414904*x^8/8! + 24130521*x^9/9! + 467773210*x^10/10! + 9636459041*x^11/11! + 215484787332*x^12/12! +...
such that A(x) is the limit of composition of functions x*exp(x^n):
A(x) = x*exp(x) o x*exp(x^2) o x*exp(x^3) o x*exp(x^4) o x*exp(x^5) o ...
working from left to right.
Illustration of generating method.
Start with F_0(x) = x and then continue as follows.
F_1(x) = x*exp(x),
F_2(x) = F_1( x*exp(x^2) ),
F_3(x) = F_2( x*exp(x^3) ),
F_4(x) = F_3( x*exp(x^4) ),
F_5(x) = F_4( x*exp(x^5) ),
...
F_{n+1}(x) = F_{n}( x*exp(x^(n+1)) ),
...
the limit of which equals the e.g.f. A(x).
The above series begin:
F_1(x) = x + 2*x^2/2! + 3*x^3/3! + 4*x^4/4! + 5*x^5/5! + 6*x^6/6! +...
F_2(x) = x + 2*x^2/2! + 9*x^3/3! + 52*x^4/4! + 245*x^5/5! + 1926*x^6/6! +...
F_3(x) = x + 2*x^2/2! + 9*x^3/3! + 76*x^4/4! + 485*x^5/5! + 5166*x^6/6! +...
F_4(x) = x + 2*x^2/2! + 9*x^3/3! + 76*x^4/4! + 605*x^5/5! + 6606*x^6/6! +...
F_5(x) = x + 2*x^2/2! + 9*x^3/3! + 76*x^4/4! + 605*x^5/5! + 7326*x^6/6! +...
...
A related series begins:
Series_Reversion(A(x)) = x - 2*x^2/2! + 3*x^3/3! - 16*x^4/4! + 385*x^5/5! - 6696*x^6/6! + 104419*x^7/7! - 1785344*x^8/8! + 37367649*x^9/9! - 986989600*x^10/10! + 30811625251*x^11/11! - 1031073660288*x^12/12! +...
		

Crossrefs

Cf. A277183 (log(A(x)/x)), A277180, A136751.
Cf. A278332.

Programs

  • PARI
    {a(n) = my(A=x +x*O(x^n)); if(n<=0, 0, for(i=1, n, A = subst(A,x, x*exp(x^i +x*O(x^n))))); n!*polcoeff(A, n)}
    for(n=1,30,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A=x+x*O(x^n)); if(n<=0, 0, for(i=1, n, A = A*exp(A^(n-i+1)))); n!*polcoeff(A, n)}
    for(n=1,30,print1(a(n),", "))

Formula

E.g.f. A(x) satisfies: Series_Reversion(A(x)) = ... (LambertW(4*x^4)/4)^(1/4) o (LambertW(3*x^3)/3)^(1/3) o (LambertW(2*x^2)/2)^(1/2) o LambertW(x), the composition of functions (LambertW(n*x^n)/n)^(1/n) for n = 1,2,3,...

A136752 G.f.: A(x) = x/(1-x) o x/(1-x^2) o x/(1-x^4) o x/(1-x^8) o..., composition of functions x/(1 - x^{2^n}) for n=0,1,2,3,...

Original entry on oeis.org

1, 1, 2, 3, 6, 10, 19, 33, 61, 108, 198, 354, 645, 1159, 2106, 3795, 6874, 12405, 22457, 40560, 73374, 132578, 239782, 433362, 783602, 1416401, 2560953, 4629393, 8369741, 15130440, 27354520, 49451349, 89401972, 161622356, 292191262
Offset: 0

Views

Author

Paul D. Hanna, Jan 21 2008

Keywords

Comments

The composition transpose of A136753.

Examples

			G.f.: A(x) is the limit of composition of functions x/(1-x^{2^n}):
F_0(x) = x/(1-x)
F_1(x) = F_1(x/(1-x^2)) = x + x^2 + 2x^3 + 3x^4 + 5x^5 + 8*x^6 + 13x^7 +...
F_2(x) = F_2(x/(1-x^4)) = x + x^2 + 2x^3 + 3x^4 + 6x^5 + 10x^6 + 19x^7 +...
F_3(x) = x/(1-x) o x/(1-x^2) o x/(1-x^4) o x/(1-x^8) =
x + x^2 + 2x^3 + 3x^4 + 6x^5 + 10x^6 + 19x^7 + 33x^8 + 61x^9 + 108x^10 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=x+x*O(x^n));if(n<=0,0,m=#binary(n+1); for(i=1,m,A=A/(1-A^(2^(m-i))));polcoeff(A,n))}

A136753 G.f.: A(x) = ...o x/(1-x^8) o x/(1-x^4) o x/(1-x^2) o x/(1-x), composition of functions x/(1 - x^{2^n}) for n=...,3,2,1,0.

Original entry on oeis.org

1, 1, 2, 4, 9, 21, 52, 134, 355, 955, 2590, 7052, 19246, 52638, 144368, 397468, 1099720, 3060936, 8577496, 24210808, 68843806, 197176726, 568585576, 1649739332, 4812731846, 14105205846, 41498665884, 122469937048
Offset: 1

Views

Author

Paul D. Hanna, Jan 21 2008

Keywords

Comments

The composition transpose of A136752.

Examples

			G.f.: A(x) is the limit of composition of functions x/(1-x^{2^n}):
F_0(x) = x/(1-x)
F_1(x) = x/(1-x^2) o F_0(x) = x + x^2 + 2x^3 + 4x^4 + 8x^5 + 16x^6 +...
F_2(x) = x/(1-x^4) o F_1(x) = x + x^2 + 2x^3 + 4x^4 + 9x^5 + 21x^6 +...
F_3(x) = x/(1-x^8) o F_2(x) = x + x^2 + 2x^3 + 4x^4 + 9x^5 + 21x^6 +...
F_4(x) = x/(1-x^16) o x/(1-x^8) o x/(1-x^4) o x/(1-x^2) o x/(1-x) =
x + x^2 + 2*x^3 + 4*x^4 + 9*x^5 + 21*x^6 + 52*x^7 + 134*x^8 + 355*x^9 +...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=x+x*O(x^n));if(n<=0,0,for(i=0,#binary(n+1),A=A/(1-A^(2^i)));polcoeff(A,n))}

A206721 G.f.: A(x) = ...o x/(1-x^7) o x/(1-x^5) o x/(1-x^3) o x/(1-x), a composition of functions x/(1-x^(2*n-1)) for n=...3,2,1.

Original entry on oeis.org

1, 1, 1, 2, 5, 12, 28, 65, 155, 387, 1002, 2641, 7016, 18743, 50321, 135608, 366399, 992221, 2693705, 7333666, 20026582, 54858122, 150739957, 415479332, 1148563576, 3183963911, 8848963329, 24650364462, 68810859415, 192439812663, 539072534278, 1512285566266
Offset: 1

Views

Author

Paul D. Hanna, Feb 11 2012

Keywords

Comments

Compositional transpose of A206720.

Examples

			G.f.: A(x) = x + x^2 + x^3 + 2*x^4 + 5*x^5 + 12*x^6 + 28*x^7 + 65*x^8 +...
where A(x) is the limit of composition of functions x/(1-x^(2*n-1)):
F_1(x) = x/(1-x)
F_2(x) = x/(1-x^3) o F_1(x) = x + x^2 + x^3 + 2*x^4 + 5*x^5 + 11*x^6 +...
F_3(x) = x/(1-x^5) o F_2(x) = x + x^2 + x^3 + 2*x^4 + 5*x^5 + 12*x^6 +...
F_4(x) = x/(1-x^7) o x/(1-x^5) o x/(1-x^3) o x/(1-x); ...
		

Crossrefs

Programs

  • PARI
    {a(n)=local(A=x+x*O(x^n)); if(n<=0, 0, for(i=1, n, A=A/(1-A^(2*i-1))); polcoeff(A, n))}
    for(n=1,45,print1(a(n),", "))
Showing 1-6 of 6 results.