

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
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OFFSET

0,1


COMMENTS

This is also the postperiod decimal digit of ((n+2)^22)/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.
G.f.: 2*(2 + 2*x + 4*x^2 + 3*x^3 + 4*x^4)/(1x^5). [corrected by Georg Fischer, May 11 2019]
Recurrence: a(n) = a(n5).


MAPLE



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



KEYWORD

nonn,easy,less


AUTHOR



EXTENSIONS

Definition simplified, offset corrected by R. J. Mathar, Sep 25 2009


STATUS

approved



