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A156138 Q_{2n+1}(sqrt(2))/sqrt(2) (see A104035). 2
1, 17, 901, 99917, 18991081, 5514615017, 2270974911661, 1258937450889317, 903952433274722641, 816101554527859690817, 904827968753139590344021, 1208617989532834039606507517, 1914312457105234828011498655801, 3547500444096776665586928259547417, 7604155838367549221056955383942297981 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..14.

FORMULA

G.f. sin(x)/(1 - 3*sin(x)^2) = x + 17*x^3/3! + 901*x^5/5! + 99917*x^7/7! + ... - Peter Bala, Feb 06 2017

MAPLE

with(gfun):

series(sin(x)/(1-3*sin(x)^2), x, 30):

L := seriestolist(%):

seq(op(2*i, L)*(2*i-1)!, i = 1..floor((1/2)*nops(L)));

# Peter Bala, Feb 06 2017

CROSSREFS

Cf. A101923, A000364, A000464, A002439.

Cf. other sequences with a g.f. of the form sin(x)/(1 - k*sin^2(x)): A101923 (k=1/2), A000364 (k=1), A000464 (k=2), A002439 (k=4).

Sequence in context: A124235 A218660 A086265 * A229261 A196873 A262386

Adjacent sequences:  A156135 A156136 A156137 * A156139 A156140 A156141

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 06 2009

STATUS

approved

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Last modified May 30 08:46 EDT 2017. Contains 287302 sequences.