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A105397
Periodic with period 2: repeat [4,2].
13
4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2
OFFSET
0,1
COMMENTS
A simple "Fractal Jump Sequence" (FJS). An FJS is a sequence of digits containing an infinite number of copies of itself. Modus operandi: underline the first digit "a" of such a sequence then jump over the next "a" digits and underline the digit "b" on which you land. Jump from there over the next "b" digits and underline the digit "c" on which you land. Etc. The "abc...n..." succession of underlined digits is the sequence itself.
Simple continued fraction of 2+sqrt(6). - R. J. Mathar, Nov 21 2011
FORMULA
a(n) = 3 + (-1)^n = 4 - 2*(n mod 2) = 2 * 2^((n+1) mod 2). - Wesley Ivan Hurt, Mar 14 2014
MAPLE
A105397:=n->3 + (-1)^n; seq(A105397(n), n=0..100); # Wesley Ivan Hurt, Mar 14 2014
MATHEMATICA
Table[3 + (-1)^n, {n, 0, 100}] (* Wesley Ivan Hurt, Mar 14 2014 *)
LinearRecurrence[{0, 1}, {4, 2}, 75] (* Ray Chandler, Aug 25 2015 *)
PROG
(PARI) contfrac(2+sqrt(6)) \\ Michel Marcus, Mar 18 2014
CROSSREFS
Cf. A010694 (period 2, repeat [2,4]).
First differences of A007310. - Fred Daniel Kline, Aug 17 2020
Sequence in context: A064127 A178253 A209272 * A373422 A328999 A236185
KEYWORD
easy,nonn
AUTHOR
Eric Angelini, May 01 2005
EXTENSIONS
Edited by N. J. A. Sloane, Jun 08 2010
STATUS
approved