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 A143432 Ultimately periodic length 4 sequence [ 2, 2, 0, 0, ...] with a(0) = a(1) = 1. 2
 1, 1, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS Table of n, a(n) for n=0..104. Index entries for linear recurrences with constant coefficients, signature (1,-1,1) FORMULA Euler transform of length 8 sequence [ 1, -1, 0, 2, 0, 0, 0, -1]. a(4*n + 2) = a(4*n + 3) = 0. a(4*n) = a(4*n + 1) = 2 unless n<1. G.f.: (1 + x^4) / ((1 - x) * (1 + x^2)). a(n)=(1/6)*{-2*(n mod 4)+[(n+1) mod 4]+4*[(n+2) mod 4]+[(n+3) mod 4]}-[C(2*n,n) mod 2]-{C[(n+1)^2,n+3] mod 2}, with n>=0 [From Paolo P. Lava, Aug 25 2008] a(n) = ((n+2) mod 4) - (n mod 2) - floor(3/(n+2)). [Wesley Ivan Hurt, Jun 30 2013] MATHEMATICA PadRight[{1, 1}, 120, {2, 2, 0, 0}] (* Harvey P. Dale, Feb 13 2016 *) PROG (PARI) {a(n) = if(n<0, 0, n = n\2; if( n%2, 0, (n>1)+1 ))} CROSSREFS Convolution inverse of A143431. Sequence in context: A341698 A357069 A033461 * A137677 A015818 A225869 Adjacent sequences: A143429 A143430 A143431 * A143433 A143434 A143435 KEYWORD nonn,easy AUTHOR Michael Somos, Aug 14 2008, Sep 18 2008 STATUS approved

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Last modified October 2 04:44 EDT 2023. Contains 365831 sequences. (Running on oeis4.)