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A170747 Expansion of g.f.: (1+x)/(1-27*x). 50
1, 28, 756, 20412, 551124, 14880348, 401769396, 10847773692, 292889889684, 7908027021468, 213516729579636, 5764951698650172, 155653695863554644, 4202649788315975388, 113471544284531335476, 3063731695682346057852, 82720755783423343562004, 2233460406152430276174108 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Kenny Lau, Table of n, a(n) for n = 0..698

Index entries for linear recurrences with constant coefficients, signature (27).

FORMULA

a(n)= Sum_{k=0..n} A097805(n,k)*(-1)^(n-k)*28^k. - Philippe Deléham, Dec 04 2009

a(0) = 1; for n > 0, a(n) = 28*27^(n-1). - Vincenzo Librandi, Dec 05 2009

E.g.f.: (28*exp(27*x) - 1)/27. - G. C. Greubel, Sep 25 2019

MAPLE

k:=28; seq(`if`(n=0, 1, k*(k-1)^(n-1)), n = 0..25); # G. C. Greubel, Sep 25 2019

MATHEMATICA

With[{k=28}, Table[If[n==0, 1, k*(k-1)^(n-1)], {n, 0, 25}]] (* G. C. Greubel, Sep 25 2019 *)

PROG

(Python) for i in range(31):print(i, 28*27**(i-1) if i>0 else 1) # Kenny Lau, Aug 03 2017

(PARI) vector(26, n, k=28; if(n==1, 1, k*(k-1)^(n-2))) \\ G. C. Greubel, Sep 25 2019

(MAGMA) k:=28; [1] cat [k*(k-1)^(n-1): n in [1..25]]; // G. C. Greubel, Sep 25 2019

(Sage) k=28; [1]+[k*(k-1)^(n-1) for n in (1..25)] # G. C. Greubel, Sep 25 2019

(GAP) k:=28;; Concatenation([1], List([1..25], n-> k*(k-1)^(n-1) )); # G. C. Greubel, Sep 25 2019

CROSSREFS

Cf. A003945, A097805.

Sequence in context: A170613 A170661 A170709 * A218730 A152127 A113532

Adjacent sequences:  A170744 A170745 A170746 * A170748 A170749 A170750

KEYWORD

nonn,easy,changed

AUTHOR

N. J. A. Sloane, Dec 04 2009

STATUS

approved

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Last modified July 24 09:52 EDT 2021. Contains 346273 sequences. (Running on oeis4.)