A009389 - OEIS

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A009389

Expansion of log(1+tanh(x))*cosh(x).

0, 1, -1, 3, -4, 5, -1, 7, -64, 9, 1319, 11, -49204, 13, 2653559, 15, -196707424, 17, 19194804719, 19, -2385684870724, 21, 367985503366799, 23, -68980888889771104, 25, 15445553274667315799, 27, -4071626956018456576564, 29

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..29.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Log[1+Tanh[x]]*Cosh[x], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Mar 09 2012 *)

CROSSREFS

From Johannes W. Meijer, May 24 2009: (Start)

The a(2*n) sequence equals the second left hand column of A160485 divided by two.

(End)

Sequence in context: A345708 A144786 A247369 * A091828 A305972 A121845

Adjacent sequences: A009386 A009387 A009388 * A009390 A009391 A009392

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved