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A001908 E.g.f. exp(-x)/(1-5*x).
(Formerly M3677 N1500)
4
1, 4, 41, 614, 12281, 307024, 9210721, 322375234, 12895009361, 580275421244, 29013771062201, 1595757408421054, 95745444505263241, 6223453892842110664, 435641772498947746481, 32673132937421080986074, 2613850634993686478885921, 222177303974463350705303284 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 83.

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

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

LINKS

T. D. Noe, Table of n, a(n) for n = 0..100

FORMULA

E.g.f. A(x) = exp(-x)/(1-5x) satisfies (1-5x)A' - (4+5x)A = 0. - Gheorghe Coserea, Aug 06 2015

a(n+1) = (5n+4) a(n) + 5n a(n-1). - Gheorghe Coserea, Aug 06 2015

a(n) = 5^n*exp(-1/5)*Gamma(n+1,-1/5), where Gamma is the incomplete Gamma function. - Robert Israel, Aug 06 2015

MAPLE

f:= gfun:-rectoproc({a(n+1) = (5*n+4)* a(n) + 5*n*a(n-1), a(0)=1, a(1)=4}, a(n), remember):

seq(f(n), n=0..30); # Robert Israel, Aug 06 2015

MATHEMATICA

nn = 20; Range[0, nn]! CoefficientList[Series[Exp[-x]/(1 - 5 x), {x, 0, nn}], x] (* T. D. Noe, Aug 17 2012 *)

PROG

(PARI) x='x+O('x^33); Vec(serlaplace(exp(-x)/(1-5*x))) \\ Gheorghe Coserea, Aug 06 2015

CROSSREFS

Sequence in context: A134277 A085340 A230251 * A270703 A192547 A006129

Adjacent sequences:  A001905 A001906 A001907 * A001909 A001910 A001911

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified December 16 09:06 EST 2019. Contains 330020 sequences. (Running on oeis4.)