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A049215 Scaled coefficients of (arctanh x)^4. 1
1, 40, 2464, 229760, 30633856, 5561407488, 1322489954304, 399463775797248, 149519094622027776, 67960463478175825920, 36884466463352967659520, 23566236397584291201024000, 17511732541318788803985408000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..12.

FORMULA

e.g.f. (arctanh x)^4 or (1-x^2)^-1 * (arctanh x)^3

a(n) is coefficient of x^(2*n+4) in (arctanh x)^4, multiplied by (2*n+4)!/4!

EXAMPLE

(arctanh x)^4 = x^4 + 4/3*x^6 + 22/15*x^8 + 1436/945*x^10 + ...

CROSSREFS

Sequence in context: A140729 A003741 A263553 * A221658 A188154 A268151

Adjacent sequences:  A049212 A049213 A049214 * A049216 A049217 A049218

KEYWORD

nonn

AUTHOR

Joe Keane (jgk(AT)jgk.org)

STATUS

approved

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Last modified November 21 11:01 EST 2018. Contains 317447 sequences. (Running on oeis4.)