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A055596 Expansion of (2-x-2/e^x)/(1-x). +0
1
1, 0, 2, 6, 32, 190, 1332, 10654, 95888, 958878, 10547660, 126571918, 1645434936, 23036089102, 345541336532, 5528661384510, 93987243536672, 1691770383660094, 32143637289541788, 642872745790835758 (list; graph; listen)
OFFSET

1,3

FORMULA

E.g.f.: (2-x-2exp(-x))/(1-x).

a(n) = (n-1)[ a(n-1) + a(n-2) ], n>2.

PROGRAM

(PARI) a(n)=if(n<2, n>0, n*a(n-1)-2*(-1)^n)

(PARI) a(n)=if(n<1, 0, n!*polcoeff((2-x-2*exp(-x+x*O(x^n)))/(1-x), n))

CROSSREFS

a(n) = n!-2 A000166(n), n>0.

Sequence in context: A092199 A108485 A018940 this_sequence A109572 A011820 A111550

Adjacent sequences: A055593 A055594 A055595 this_sequence A055597 A055598 A055599

KEYWORD

nonn

AUTHOR

Gary Detlefs (gdetlefs(AT)absolute-net.com), Jul 10 2000

EXTENSIONS

More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 11 2000

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.


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