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A153596 a(n) = ((5+sqrt(3))^n-(5-sqrt(3))^n)/(2*sqrt(3)). 1
1, 10, 78, 560, 3884, 26520, 179752, 1214080, 8186256, 55152800, 371430368, 2500942080, 16837952704, 113358801280, 763153053312, 5137636904960, 34587001876736, 232842006858240, 1567506027294208, 10552536122060800 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Third binomial transform of A054485. Fifth binomial transform of A162813 preceded by 1.

lim_{n -> infinity} a(n)/a(n-1) = 5+sqrt(3) = 6.73205080756887729....

FORMULA

G.f.: x/(1-10*x+22*x^2). [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Dec 31 2008, corrected Oct 11 2009]

a(n) = 10*a(n-1)-22*a(n-2) for n>1; a(0)=0, a(1)=1. [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 01 2009]

MATHEMATICA

Join[{a=1, b=10}, Table[c=10*b-22*a; a=b; b=c, {n, 60}]] (*From Vladimir Joseph Stephan Orlovsky, Jan 27 2011*)

PROG

(MAGMA) Z<x>:= PolynomialRing(Integers()); N<r>:=NumberField(x^2-3); S:=[ ((5+r)^n-(5-r)^n)/(2*r): n in [1..20] ]; [ Integers()!S[j]: j in [1..#S] ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Dec 31 2008]

(Other) Sage: [lucas_number1(n, 10, 22) for n in xrange(1, 21)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 26 2009]

CROSSREFS

Cf. A002194 (decimal expansion of sqrt(3)), A054485, A162813.

Sequence in context: A016201 A080618 A082136 * A056986 A160655 A006469

Adjacent sequences:  A153593 A153594 A153595 * A153597 A153598 A153599

KEYWORD

nonn

AUTHOR

Al Hakanson (hawkuu(AT)gmail.com), Dec 29 2008

EXTENSIONS

Extended beyond a(7) by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Dec 31 2008

Edited by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 11 2009

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Last modified February 16 12:41 EST 2012. Contains 205909 sequences.