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A165662 Period 5: repeat 4,4,8,6,8. 1
4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8, 4, 4, 8, 6, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
This is also the post-period decimal digit of ((n+2)^2-2)/5.
Serves also as the decimal expansion of 1495600/33333 and as the continued fraction representation of (33397+sqrt(12952802))/1649.
LINKS
FORMULA
a(n) = (2*n^2 + 8*n + 4) mod 10.
From Wesley Ivan Hurt, Sep 06 2014: (Start)
G.f.: 2*(2 + 2*x + 4*x^2 + 3*x^3 + 4*x^4)/(1-x^5). [corrected by Georg Fischer, May 11 2019]
Recurrence: a(n) = a(n-5).
a(n) = (2*A008865(n+1)) mod 10.
a(n) = (-A147973(n+4)) mod 10.
a(n+1) = 2*A053796(n) + 4. (End)
MAPLE
A165662:=n->2*n^2+8*n+4 mod 10: seq(A165662(n), n=0..100); # Wesley Ivan Hurt, Sep 06 2014
MATHEMATICA
Table[Mod[2 n^2 + 8 n + 4, 10], {n, 0, 100}] (* Wesley Ivan Hurt, Sep 06 2014 *)
CoefficientList[Series[2 (2 + 2 x + 4 x^2 + 3 x^3 + 4 x^4)/(1 - x^5), {x, 0, 30}], x] (* Wesley Ivan Hurt, Sep 06 2014 *)
PROG
(Magma) [(2*n^2+8*n+4) mod 10 : n in [0..100]]; // Wesley Ivan Hurt, Sep 06 2014
(PARI) a(n)=[4, 4, 8, 6, 8][n%5+1] \\ Edward Jiang, Sep 06 2014
CROSSREFS
Sequence in context: A254267 A028266 A275982 * A110648 A198936 A289091
KEYWORD
nonn,easy,less
AUTHOR
Vincenzo Librandi, Sep 24 2009
EXTENSIONS
Definition simplified, offset corrected by R. J. Mathar, Sep 25 2009
Name and offset changed by Wesley Ivan Hurt, Sep 06 2014
STATUS
approved

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Last modified May 28 04:02 EDT 2024. Contains 372900 sequences. (Running on oeis4.)