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A049381 Expansion of (1-25*x)^(-3/5). 5
1, 15, 300, 6500, 146250, 3363750, 78487500, 1850062500, 43938984375, 1049653515625, 25191684375000, 606890578125000, 14666522304687500, 355381117382812500, 8630684279296875000, 210013317462890625000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..15.

FORMULA

G.f.: (1-25*x)^(-3/5).

a(n) = (5^n/n!) * product[ k=0..n-1 ] (5*k+3).

a(n) ~ Gamma(3/5)^-1*n^(-2/5)*5^(2*n)*{1 - 3/25*n^-1 + ...}. - Joe Keane (jgk(AT)jgk.org), Nov 24 2001

a(n) = (-25)^n*binomial(-3/5, n). - Peter Luschny, Oct 23 2018

EXAMPLE

(1-x)^(-3/5) = 1 + 3/5*x + 12/25*x^2 + 52/125*x^3 + ...

MAPLE

A049381 := n -> (-25)^n*binomial(-3/5, n):

seq(A049381(n), n=0..16); # Peter Luschny, Oct 23 2018

MATHEMATICA

CoefficientList[Series[(1-25x)^(-3/5), {x, 0, 20}], x] (* Harvey P. Dale, Aug 08 2013 *)

CROSSREFS

Cf. A049382, A049392, A049396, A049380, A049382.

Sequence in context: A201341 A144349 A009064 * A051691 A247238 A135390

Adjacent sequences:  A049378 A049379 A049380 * A049382 A049383 A049384

KEYWORD

nonn,easy

AUTHOR

Joe Keane (jgk(AT)jgk.org)

STATUS

approved

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Last modified May 30 05:35 EDT 2020. Contains 334712 sequences. (Running on oeis4.)