A202617 -id:A202617 - cp's OEIS frontend

A349719 E.g.f. satisfies: A(x) = exp( x * (1 + 1/A(x))/2 ).

1, 1, 0, 1, -4, 26, -212, 2108, -24720, 334072, -5112544, 87396728, -1650607040, 34132685120, -767025716736, 18612106195456, -485013257865472, 13509071081429888, -400505695457942528, 12592502771190979712, -418524228123134068224

Offset: 0

Seiichi Manyama, Nov 27 2021

sign

Seiichi Manyama, Table of n, a(n) for n = 0..411
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A283828, A349714, A349715, A349716, A349720, A349721.

a[n_] := (1/2^n) * Sum[If[k == n == 1, 1, (-k + 1)^(n - 1)] * Binomial[n, k], {k, 0, n}]; Array[a, 21, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (-k+1)^(n-1)*binomial(n, k))/2^n;

my(N=40, x='x+O('x^N)); Vec(serlaplace((x/2)/lambertw(x/2*exp(-x/2))))

my(N=40, x='x+O('x^N)); Vec(2*sum(k=0, N, (-k+1)^(k-1)*x^k/(2-(-k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (-k+1)^(n-1) * binomial(n,k).
E.g.f.: (x/2)/LambertW( x/2 * exp(-x/2) ).
G.f.: 2 * Sum_{k>=0} (-k+1)^(k-1) * x^k/(2 - (-k+1)*x)^(k+1).
a(n) ~ -(-1)^n * sqrt(1 + LambertW(exp(-1))) * n^(n-1) / (2^n * exp(n) * LambertW(exp(-1))^(n-1)). - Vaclav Kotesovec, Dec 05 2021

A214225 E.g.f. satisfies: A(x) = x/(1 - tanh(A(x))).

Original entry on oeis.org

1, 2, 12, 112, 1440, 23616, 471296, 11085824, 300349440, 9211187200, 315448860672, 11932326789120, 494098626904064, 22230301612703744, 1079857012109475840, 56326462301645307904, 3140024293968001892352, 186308007164786201591808, 11722541029509094870876160

Offset: 1

Paul D. Hanna, Jul 07 2012

nonn

			E.g.f.: A(x) = x + 2*x^2/2! + 12*x^3/3! + 112*x^4/4! + 1440*x^5/5! +...
Related expansions:
A(x) = x + x*tanh(x) + d/dx x^2*tanh(x)^2/2! + d^2/dx^2 x^3*tanh(x)^3/3! + d^3/dx^3 x^4*tanh(x)^4/4! +...
log(A(x)/x) = tanh(x) + d/dx x*tanh(x)^2/2! + d^2/dx^2 x^2*tanh(x)^3/3! + d^3/dx^3 x^3*tanh(x)^4/4! +...
A(x)/x = 1 + x + 4*x^2/2! + 28*x^3/3! + 288*x^4/4! + 3936*x^5/5! + 67328*x^6/6! +...+ A201595(n)*x^n/n! +...
tanh(A(x)) = x + 2*x^2/2! + 10*x^3/3! + 88*x^4/4! + 1096*x^5/5! + 17616*x^6/6! + 346704*x^7/7! + 8072576*x^8/8! +...

G. C. Greubel, Table of n, a(n) for n = 1..370

Cf. A201595, A202617, A214222, A214223, A214224.

Rest[CoefficientList[InverseSeries[Series[x-x*Tanh[x],{x,0,20}],x],x]*Range[0,20]!] (* Vaclav Kotesovec, Sep 17 2013 *)
Flatten[{1,Table[1/2*Sum[Binomial[n,k]*k^(n-1),{k,0,n}],{n,2,20}]}] (* Vaclav Kotesovec, Sep 17 2013 *)

{a(n)=(1/2)*sum(k=0,n,binomial(n,k)*k^(n-1))}
for(n=1, 25, print1(a(n), ", "))

{a(n)=(n-1)!*polcoeff(x/(1 - tanh(x+x*O(x^n)))^n,n)}

{a(n)=n!*polcoeff(serreverse(x-x*tanh(x+x*O(x^n))), n)}

{a(n)=n!*polcoeff(sum(k=1, n, k^(k-1)*cosh(k*x +x*O(x^n))*x^k/k! +x*O(x^n)), n)} \\ Paul D. Hanna, Nov 20 2012
for(n=1, 25, print1(a(n), ", "))

{Dx(n, F)=local(D=F); for(i=1, n, D=deriv(D)); D}
{a(n)=local(A=x); A=x+sum(m=1, n, Dx(m-1, x^m*tanh(x+x*O(x^n))^m/m!)); n!*polcoeff(A, n)}

{Dx(n, F)=local(D=F); for(i=1, n, D=deriv(D)); D}
{a(n)=local(A=x+x^2+x*O(x^n)); A=x*exp(sum(m=1, n, Dx(m-1, x^(m-1)*tanh(x+x*O(x^n))^m/m!)+x*O(x^n))); n!*polcoeff(A, n)}

E.g.f. A(x) satisfies:
(1) A(x - x*tanh(x)) = x.
(2) A(x) = x + Sum_{n>=1} d^(n-1)/dx^(n-1) x^n*tanh(x)^n/n!.
(3) A(x) = x*exp( Sum_{n>=1} d^(n-1)/dx^(n-1) x^(n-1)*tanh(x)^n/n! ).
(4) A(x) = Sum_{n>=1} n^(n-1) * cosh(n*x) * x^n / n!. - Paul D. Hanna, Nov 20 2012
(5) A(x) = log(G(x)) where G(x) = exp(x*(1+G(x)^2)/2) is the e.g.f. of A202617. - Paul D. Hanna, Nov 20 2012
a(n) = n*A201595(n-1).
a(n) = (1/2)*Sum_{k=0..n} binomial(n,k)*k^(n-1).
a(n) = (n-1)! * [x^n] x/(1 - tanh(x))^n.
a(n) = A038049(n)/2. - R. J. Mathar, Peter Bala, Mar 24 2013
a(n) ~ 1/2 * n^(n-1) * sqrt((1+LambertW(1/exp(1)))) / (exp(1)*LambertW(1/exp(1)))^n. - Vaclav Kotesovec, Sep 17 2013

A349714 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^3)/2 ).

Original entry on oeis.org

1, 1, 4, 37, 532, 10426, 259300, 7823908, 277713904, 11339452792, 523621438336, 26982030104536, 1534947906550528, 95550736737542464, 6460746383585984512, 471533064029919744256, 36946948091091750496000, 3093472887944746070621056

Offset: 0

Seiichi Manyama, Nov 26 2021

nonn

Seiichi Manyama, Table of n, a(n) for n = 0..352
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A349715, A349716, A349719, A349720, A349721.

a[n_] := (1/2^n) * Sum[(3*k + 1)^(n - 1) * Binomial[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (3*k+1)^(n-1)*binomial(n, k))/2^n;

my(N=20, x='x+O('x^N)); Vec(serlaplace((-lambertw(-3*x/2*exp(3*x/2))/(3*x/2))^(1/3)))

my(N=20, x='x+O('x^N)); Vec(2*sum(k=0, N, (3*k+1)^(k-1)*x^k/(2-(3*k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (3*k+1)^(n-1) * binomial(n,k).
E.g.f.: ( -LambertW( -3*x/2 * exp(3*x/2) )/(3*x/2) )^(1/3).
G.f.: 2 * Sum_{k>=0} (3*k+1)^(k-1) * x^k/(2 - (3*k+1)*x)^(k+1).
a(n) ~ sqrt(1 + LambertW(exp(-1))) * 3^(n-1) * n^(n-1) / (LambertW(exp(-1))^(n + 1/3) * 2^n * exp(n)). - Vaclav Kotesovec, Nov 26 2021

A349716 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^5)/2 ).

Original entry on oeis.org

1, 1, 6, 91, 2156, 69926, 2884576, 144555356, 8529135216, 579220982056, 44503081624976, 3816776859516776, 361462121953291456, 37464997600663289216, 4218485281787859411456, 512762346462142021355776, 66919363061333997572830976, 9332997074366800051673277056

Offset: 0

Seiichi Manyama, Nov 26 2021

nonn

Seiichi Manyama, Table of n, a(n) for n = 0..330
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A349714, A349715, A349719, A349720, A349721.

a[n_] := (1/2^n) * Sum[(5*k + 1)^(n - 1) * Binomial[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (5*k+1)^(n-1)*binomial(n, k))/2^n;

my(N=20, x='x+O('x^N)); Vec(serlaplace((-lambertw(-5*x/2*exp(5*x/2))/(5*x/2))^(1/5)))

my(N=20, x='x+O('x^N)); Vec(2*sum(k=0, N, (5*k+1)^(k-1)*x^k/(2-(5*k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (5*k+1)^(n-1) * binomial(n,k).
E.g.f.: ( -LambertW( -5*x/2 * exp(5*x/2) )/(5*x/2) )^(1/5).
G.f.: 2 * Sum_{k>=0} (5*k+1)^(k-1) * x^k/(2 - (5*k+1)*x)^(k+1).
a(n) ~ sqrt(1 + LambertW(exp(-1))) * 5^(n-1) * n^(n-1) / (LambertW(exp(-1))^(n + 1/5) * 2^n * exp(n)). - Vaclav Kotesovec, Nov 26 2021

A349720 E.g.f. satisfies: A(x) = exp( x * (1 + 1/A(x)^2)/2 ).

Original entry on oeis.org

1, 1, -1, 7, -63, 801, -13025, 258343, -6048511, 163276417, -4992740289, 170571634311, -6439161507647, 266180947507489, -11958385377911713, 580151397382158631, -30227616424300542975, 1683438461080186841601, -99796591057813372007297

Offset: 0

Seiichi Manyama, Nov 27 2021

sign

Seiichi Manyama, Table of n, a(n) for n = 0..372
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A349714, A349715, A349716, A349719, A349721.

a[n_] := (1/2^n) * Sum[(-2*k + 1)^(n - 1) * Binomial[n, k], {k, 0, n}]; Array[a, 19, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (-2*k+1)^(n-1)*binomial(n, k))/2^n;

my(N=20, x='x+O('x^N)); Vec(serlaplace((x/lambertw(x*exp(-x)))^(1/2)))

my(N=20, x='x+O('x^N)); Vec(2*sum(k=0, N, (-2*k+1)^(k-1)*x^k/(2-(-2*k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (-2*k+1)^(n-1) * binomial(n,k).
E.g.f.: ( x/LambertW( x * exp(-x) ) )^(1/2).
G.f.: 2 * Sum_{k>=0} (-2*k+1)^(k-1) * x^k/(2 - (-2*k+1)*x)^(k+1).
a(n) ~ -(-1)^n * sqrt(1 + LambertW(exp(-1))) * n^(n-1) / (2 * exp(n) * LambertW(exp(-1))^(n - 1/2)). - Vaclav Kotesovec, Dec 05 2021

A362694 E.g.f. satisfies A(x) = exp(x + x * A(x)^2).

Original entry on oeis.org

1, 2, 12, 152, 2960, 78112, 2607808, 105432448, 5008584960, 273482293760, 16878251101184, 1161918967060480, 88277165100666880, 7337286679766179840, 662287143981044121600, 64516370031367063175168, 6746443728505612426870784, 753763691778003738319519744

Offset: 0

Seiichi Manyama, May 01 2023

nonn

Seiichi Manyama, Table of n, a(n) for n = 0..339
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A349562, A362693, A362734, A362735.

Cf. A143768, A202617.

my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(x-lambertw(-2*x*exp(2*x))/2)))

E.g.f.: sqrt( -LambertW(-2*x*exp(2*x)) / (2*x) ) = exp( x - LambertW(-2*x*exp(2*x))/2 ).
a(n) = Sum_{k=0..n} (2*k+1)^(n-1) * binomial(n,k) = 2^n * A202617(n).
a(n) ~ sqrt(1 + 1/LambertW(exp(-1))) * 2^(n-1) * n^(n-1) / (exp(n) * LambertW(exp(-1))^n). - Vaclav Kotesovec, Nov 10 2023

A349715 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^4)/2 ).

Original entry on oeis.org

1, 1, 5, 61, 1161, 30201, 998413, 40077493, 1893550865, 102951388657, 6331847746581, 434653328279853, 32944254978940825, 2732662648183661545, 246228744062320481309, 23949858491053731087781, 2501088964314980938821153, 279111248034686114681365473

Offset: 0

Seiichi Manyama, Nov 26 2021

nonn

Seiichi Manyama, Table of n, a(n) for n = 0..339
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A349714, A349716, A349719, A349720, A349721.

a[n_] := (1/2^n) * Sum[(4*k + 1)^(n - 1) * Binomial[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (4*k+1)^(n-1)*binomial(n, k))/2^n;

my(N=20, x='x+O('x^N)); Vec(serlaplace((-lambertw(-2*x*exp(2*x))/(2*x))^(1/4)))

my(N=20, x='x+O('x^N)); Vec(2*sum(k=0, N, (4*k+1)^(k-1)*x^k/(2-(4*k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (4*k+1)^(n-1) * binomial(n,k).
E.g.f.: ( -LambertW( -2*x * exp(2*x) )/(2*x) )^(1/4).
G.f.: 2 * Sum_{k>=0} (4*k+1)^(k-1) * x^k/(2 - (4*k+1)*x)^(k+1).
a(n) ~ sqrt(1 + LambertW(exp(-1))) * 2^(n-2) * n^(n-1) / (LambertW(exp(-1))^(n + 1/4) * exp(n)). - Vaclav Kotesovec, Nov 26 2021

A349721 E.g.f. satisfies: A(x) = exp( x * (1 + 1/A(x)^3)/2 ).

Original entry on oeis.org

1, 1, -2, 19, -260, 4966, -121328, 3613996, -127035920, 5147600680, -236245559984, 12112405259560, -686148484748480, 42560312499982720, -2868921992458611200, 208828244778853125376, -16324500711130356582656, 1363986660232205656646272

Offset: 0

Seiichi Manyama, Nov 27 2021

sign

Seiichi Manyama, Table of n, a(n) for n = 0..352
Eric Weisstein's World of Mathematics, Lambert W-Function.

Cf. A007889, A202617, A349714, A349715, A349716, A349719, A349720.

a[n_] := (1/2^n) * Sum[(-3*k + 1)^(n - 1) * Binomial[n, k], {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Nov 27 2021 *)

a(n) = sum(k=0, n, (-3*k+1)^(n-1)*binomial(n, k))/2^n;

my(N=20, x='x+O('x^N)); Vec(serlaplace(((3*x/2)/lambertw(3*x/2*exp(-3*x/2)))^(1/3)))

my(N=20, x='x+O('x^N)); Vec(2*sum(k=0, N, (-3*k+1)^(k-1)*x^k/(2-(-3*k+1)*x)^(k+1)))

a(n) = (1/2^n) * Sum_{k=0..n} (-3*k+1)^(n-1) * binomial(n,k).
E.g.f.: ( (3*x/2)/LambertW( 3*x/2 * exp(-3*x/2) ) )^(1/3).
G.f.: 2 * Sum_{k>=0} (-3*k+1)^(k-1) * x^k/(2 - (-3*k+1)*x)^(k+1).
a(n) ~ -(-1)^n * sqrt(1 + LambertW(exp(-1))) * 3^(n-1) * n^(n-1) / (2^n * exp(n) * LambertW(exp(-1))^(n - 1/3)). - Vaclav Kotesovec, Dec 05 2021

cp's OEIS Frontend

A349719 E.g.f. satisfies: A(x) = exp( x * (1 + 1/A(x))/2 ).

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A214225 E.g.f. satisfies: A(x) = x/(1 - tanh(A(x))).

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A349714 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^3)/2 ).

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A349716 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^5)/2 ).

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A349720 E.g.f. satisfies: A(x) = exp( x * (1 + 1/A(x)^2)/2 ).

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A362694 E.g.f. satisfies A(x) = exp(x + x * A(x)^2).

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A349715 E.g.f. satisfies: A(x) = exp( x * (1 + A(x)^4)/2 ).

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