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A138019
Period 5: repeat [1, 1, 0, -1, -1].
3
1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1, -1, 1, 1, 0, -1
OFFSET
0,1
FORMULA
Inverse binomial transform of A138003.
O.g.f.: (1+x)(x^2+x+1)/(1+x+x^2+x^3+x^4). - R. J. Mathar, Jun 28 2008
Euler transform of length 5 sequence [ 1, -1, -1, 0, 1]. - Michael Somos, Jun 17 2015
G.f.: (1 - x^2 ) * (1 - x^3) / ((1 - x) * (1 - x^5)). - Michael Somos, Jun 17 2015
a(n) = -a(-1-n) = a(n+5) for all n in Z. - Michael Somos, Jun 17 2015
EXAMPLE
G.f. = 1 + x - x^3 - x^4 + x^5 + x^6 - x^8 - x^9 + x^10 + x^11 - x^13 + ...
MAPLE
A138019 := proc(n)
op( 1+modp(n, 5), [1, 1, 0, -1, -1]) ;
end proc:
seq(A138019(n), n=0..30) ; # R. J. Mathar, Feb 12 2021
MATHEMATICA
a[ n_] := Sign[2 - Mod[n, 5]]; (* Michael Somos, Jun 17 2015 *)
PadRight[{}, 120, {1, 1, 0, -1, -1}] (* Harvey P. Dale, Oct 06 2023 *)
PROG
(PARI) a(n)=sign(2-n%5) /* Jaume Oliver Lafont, Aug 28 2009 */
CROSSREFS
Sequence in context: A305387 A085241 A105368 * A179850 A267919 A097343
KEYWORD
easy,sign
AUTHOR
Paul Curtz, May 01 2008
STATUS
approved