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%I #33 Mar 08 2024 01:12:14
%S 6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,
%T 2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,
%U 2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2,6,4,2,4,2,4,6,2
%N First differences of A007775.
%C Also the first differences of A084968 divided by 7. - _Antti Karttunen_, May 01 2015
%H Reinhard Zumkeller, <a href="/A145011/b145011.txt">Table of n, a(n) for n = 1..10000</a>
%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,1).
%F Period 8: repeat 6,4,2,4,2,4,6,2.
%F a(n) = 2*((abs(abs((n mod 8) - 3) - 1) mod 3) + 1). - _Pieter Stadhouders_, Mar 09 2010
%F G.f.: x*(-2*x^7 - 6*x^6 - 4*x^5 - 2*x^4 - 4*x^3 - 2*x^2 - 4*x - 6)/(x^8 - 1). - _Chai Wah Wu_, Feb 16 2021
%t Differences[Select[Range[400],GCD[#,30]==1&]] (* _Harvey P. Dale_, Dec 07 2011 *)
%o (Haskell)
%o a145011 n = a145011_list !! (n-1)
%o a145011_list = zipWith (-) (tail a007775_list) a007775_list
%o -- _Reinhard Zumkeller_, Jan 06 2013
%o (PARI) a(n)=[4,6,4,2,4,2][n%8+1] \\ _Charles R Greathouse IV_, Oct 20 2013
%Y Cf. A007775, A084968.
%Y Multiplied by 7: row 4 of A257251.
%K nonn,easy
%O 1,1
%A _Ki Punches_, Feb 25 2009
%E Edited by _Omar E. Pol_, Mar 02 2009
%E Offset corrected by _Reinhard Zumkeller_, Jan 06 2013
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