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A068379 Engel expansion of sinh(1/2). 1
1, 24, 80, 168, 288, 440, 624, 840, 1088, 1368, 1680, 2024, 2400, 2808, 3248, 3720, 4224, 4760, 5328, 5928, 6560, 7224, 7920, 8648, 9408, 10200, 11024, 11880, 12768, 13688, 14640, 15624, 16640, 17688, 18768, 19880, 21024, 22200, 23408, 24648, 25920, 27224 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Cf. A006784 for Engel expansion definition.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(0) = 1, a(n) = 4*n*(4n+2).

a(n) = 3*a(n-1)-3*a(n-2)+a(n-3) for n>3. G.f.: (1+21*x+11*x^2-x^3)/(1-x)^3. - Colin Barker, Apr 13 2012

MATHEMATICA

Table[If[n==0, 1, 4n*(4n+2)], {n, 0, 50}] (* Vladimir Joseph Stephan Orlovsky, Jan 30 2012 *)

LinearRecurrence[{3, -3, 1}, {1, 24, 80, 168}, 50] (* Harvey P. Dale, Mar 21 2017 *)

PROG

(MAGMA) [1] cat [4*n*(4*n+2): n in [1..50]]; // Vincenzo Librandi, Jan 31 2012

(PARI) a(n)=if(n, 4*n*(4*n+2), 1) \\ Charles R Greathouse IV, Jan 31 2012

CROSSREFS

Sequence in context: A206003 A143839 A114818 * A190102 A060673 A167561

Adjacent sequences:  A068376 A068377 A068378 * A068380 A068381 A068382

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Mar 03 2002

STATUS

approved

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Last modified October 17 01:03 EDT 2019. Contains 328103 sequences. (Running on oeis4.)