The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A080460 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A080460

a(1) = 2; for n > 1, a(n) = a(n-1) if n is already in the sequence, a(n) = a(n-1) + 4 otherwise.
(history; published version)

#22 by Susanna Cuyler at Mon Jan 07 11:16:07 EST 2019

STATUS

proposed

approved

#21 by Franck Maminirina Ramaharo at Mon Jan 07 11:12:01 EST 2019

STATUS

editing

proposed

#20 by Franck Maminirina Ramaharo at Mon Jan 07 11:11:53 EST 2019

NAME

a(1) = 2; for n > 1, a(n) = a(n-1) if n is already in the sequence, a(n) = a(n-1) + 4 otherwise.

FORMULA

a(n) = 2 + 4*(n - 2 - floor((n - 2)/4)).

a(n) = (6*n - (-1)^n + 2*sqrt(2)*sin(Pi*n/2 + Pi/4) - 5)/2. (End)

STATUS

proposed

editing

#19 by Jean-François Alcover at Mon Jan 07 09:54:23 EST 2019

STATUS

editing

proposed

#18 by Jean-François Alcover at Mon Jan 07 09:54:20 EST 2019

MATHEMATICA

LinearRecurrence[{1, 0, 0, 1, -1}, {2, 2, 6, 10, 14}, 58] (* Jean-François Alcover, Jan 07 2019 *)

STATUS

approved

editing

#17 by N. J. A. Sloane at Sun Jul 17 19:48:30 EDT 2016

STATUS

proposed

approved

#16 by Charles R Greathouse IV at Sun Jul 17 17:56:01 EDT 2016

STATUS

editing

proposed

#15 by Charles R Greathouse IV at Sun Jul 17 17:55:52 EDT 2016

LINKS

<a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1).

PROG

(PARI) a(n)=4*n - (n-2)\4*4 - 6 \\ Charles R Greathouse IV, Jul 17 2016

KEYWORD

nonn,changed,easy

STATUS

proposed

editing

#14 by Michel Marcus at Sun Jul 17 16:44:26 EDT 2016

STATUS

editing

proposed

#13 by Michel Marcus at Sun Jul 17 16:44:18 EDT 2016

LINKS

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (, arXiv:math.NT/0305308) [math.NT], 2003.

CROSSREFS

Cf. A080455-, A080456, A080457, A080458, A080036, A080037.

STATUS

proposed

editing