A104042 -id:A104042 - cp's OEIS frontend

A098087 Numerators of coefficients in expansion of x^2(1-exp(-2x))^(-2).

1, 1, 5, 1, 1, -1, -1, 1, 1, -1, -1, 1, 691, -691, -1, 2, 3617, -3617, -43867, 43867, 174611, -174611, -77683, 155366, 236364091, -236364091, -657931, 1315862, 3392780147, -6785560294, -3446336510402, 6892673020804, 7709321041217, -7709321041217, -151628697551, 151628697551

Offset: 0

N. J. A. Sloane, Apr 17 2005

Suggested by Bill Gosper's remarkable identity (in a posting to math-fun list, Apr 14 2005) (replace dots by spaces to make this more visible): Product_{ n >= 0 } tanh(2^n x)^(1/2^n) = (1-exp(-2*x))^2.

Cf. A104007, A104042, A104097.

A104097 Denominators of coefficients in expansion of x^-2(1-exp(-2x))^2.

Original entry on oeis.org

1, 1, 3, 1, 45, 5, 315, 189, 2025, 4725, 467775, 1485, 42567525, 212837625, 91216125, 42567525, 97692469875, 516891375, 9280784638125, 236238154425, 43752270436875, 714620417135625, 147926426347074375, 53123043290625, 48076088562799171875

Offset: 0

N. J. A. Sloane, Apr 18 2005

Robert Israel, Table of n, a(n) for n = 0..504

See A104042 for more information.

S:= series(x^(-2)*(1-exp(-2*x))^2, x, 32):
seq(denom(coeff(S, x, j)), j=0..31); # Robert Israel, Aug 12 2019

cp's OEIS Frontend

A098087 Numerators of coefficients in expansion of x^2(1-exp(-2x))^(-2).

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A104097 Denominators of coefficients in expansion of x^-2(1-exp(-2x))^2.

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cp's OEIS Frontend

A098087 Numerators of coefficients in expansion of x^2*(1-exp(-2*x))^(-2).

Views

Author

Keywords

Comments

Crossrefs

A104097 Denominators of coefficients in expansion of x^-2*(1-exp(-2*x))^2.

Views

Author

Keywords

Links

Crossrefs

Programs

Maple

A098087 Numerators of coefficients in expansion of x^2(1-exp(-2x))^(-2).

A104097 Denominators of coefficients in expansion of x^-2(1-exp(-2x))^2.