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A000318 Generalized tangent numbers.
(Formerly M3713 N1517)
+0
1
4, 128, 16384, 4456448, 2080374784, 1483911200768, 1501108249821184, 2044143848640217088, 3605459138582973251584, 7995891855149741436305408, 21776918737280678860353961984, 71454103701490016776039304265728 (list; graph; listen)
OFFSET

1,1

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

D. Shanks, Generalized Euler and class numbers, Math. Comp. 21 (1967), 689-694; 22 (1968), 699.

LINKS

Thomas Baruchel, Home Page

FORMULA

The g.f. has the following continued fraction expansion: g.f. = [4, b(0), c(0), b(1), c(1), b(2), c(2), ...] where b(n) = sum(k=0, n, 1/(2*k+1))^2 / (128*(n+1)*x), c(n) = -4/( sum(k=0, n, 1/(2*k+1))*sum(k=0, n+1, 1/(2*k+1))*(2*n+3) ) and each convergent of this continued fraction is a Pad'e approximant of the McLaurin series sum(k=1, \infty, a(n)*x^(n-1)). - Thomas Baruchel, Oct 19 2005

CROSSREFS

Equals 2^(4n-2) * A000182(n).

Sequence in context: A128790 A013823 A130318 this_sequence A141367 A141368 A146555

Adjacent sequences: A000315 A000316 A000317 this_sequence A000319 A000320 A000321

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 03 2000

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.


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