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A098401 (0^n+3^n*Binomial(2n,n))/2. 2
1, 3, 27, 270, 2835, 30618, 336798, 3752892, 42220035, 478493730, 5454828522, 62482581252, 718549684398, 8290957896900, 95938227092700, 1112883434275320, 12937269923450595, 150681143814306930, 1757946677833580850, 20540219077844997300 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A098401(n+1)=3*A098399(n).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..900

FORMULA

G.f.: 6x/(sqrt(1-12x)(1-sqrt(1-12x)).

n*a(n) +6*(-2*n+1)*a(n-1)=0. - R. J. Mathar, Nov 24 2012

PROG

(MAGMA) [(0^n + 3^n * Binomial(2*n, n))/2: n in [ 0..20]]; // Vincenzo Librandi, Nov 24 2012

CROSSREFS

Cf. A069723, A069720.

Sequence in context: A026294 A199688 A275998 * A011544 A127503 A214363

Adjacent sequences:  A098398 A098399 A098400 * A098402 A098403 A098404

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Sep 06 2004

STATUS

approved

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Last modified January 19 18:25 EST 2020. Contains 331051 sequences. (Running on oeis4.)