A145011 First differences of A007775.

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, 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, 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

Offset

1,1

Comments

Also the first differences of A084968 divided by 7. - Antti Karttunen, May 01 2015

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,1).

Formula

Period 8: repeat 6,4,2,4,2,4,6,2.

a(n) = 2*((abs(abs((n mod 8) - 3) - 1) mod 3) + 1). - Pieter Stadhouders, Mar 09 2010

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

Mathematica

Differences[Select[Range[400], GCD[#, 30]==1&]] (* Harvey P. Dale, Dec 07 2011 *)

Prog

(Haskell)
a145011 n = a145011_list !! (n-1)
a145011_list = zipWith (-) (tail a007775_list) a007775_list
-- Reinhard Zumkeller, Jan 06 2013
(PARI) a(n)=[4, 6, 4, 2, 4, 2][n%8+1] \\ Charles R Greathouse IV, Oct 20 2013

Crossrefs

Cf. A007775, A084968.

Multiplied by 7: row 4 of A257251.

Sequence in context: A338136 A388330 A028975 * A173625 A086036 A394105

Adjacent sequences: A145008 A145009 A145010 * A145012 A145013 A145014

Keyword

nonn,easy

Author

Ki Punches, Feb 25 2009

Extensions

Edited by Omar E. Pol, Mar 02 2009

Offset corrected by Reinhard Zumkeller, Jan 06 2013

Status

approved