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A085364 a(0)=1, for n>0: a(n)=6*13^(n-1)-(1/2)Sum a(i)a(n-i),(i=1,..,n-1). 1
1, 6, 60, 654, 7458, 87378, 1042152, 12587730, 153479508, 1885010946, 23285957604, 289018502682, 3601315495050, 45023019250398, 564465885846216, 7094214579174558, 89351097367355826, 1127492973620753010 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

FORMULA

G.f.: sqrt((1-x)/(1-13*x))

13^n = sum(i=0..n, sum(j=0..i, a(j)*a(i-j) )).

Recurrence: n*a(n) = 2*(7*n-4)*a(n-1) - 13*(n-2)*a(n-2). - Vaclav Kotesovec, Oct 14 2012

a(n) ~ 2*sqrt(3)*13^(n-1/2)/sqrt(Pi*n). - Vaclav Kotesovec, Oct 14 2012

MATHEMATICA

CoefficientList[Series[Sqrt[(1-x)/(1-13x)], {x, 0, 25}], x]

PROG

(PARI) x='x+O('x^66); Vec(sqrt((1-x)/(1-13*x))) \\ Joerg Arndt, May 10 2013

CROSSREFS

Cf. A085362, A085363.

Sequence in context: A186672 A295503 A106259 * A228484 A232969 A232246

Adjacent sequences:  A085361 A085362 A085363 * A085365 A085366 A085367

KEYWORD

easy,nonn

AUTHOR

Mario Catalani (mario.catalani(AT)unito.it), Jun 25 2003

STATUS

approved

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Last modified December 15 08:50 EST 2018. Contains 318148 sequences. (Running on oeis4.)