A091086 - OEIS

A091086

a(n) = A000975(n) mod 10.

0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0, 1, 2, 5, 0

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OFFSET

0,3

COMMENTS

A000975(0), A000975(1), A000975(2), A000975(3) repeating.

LINKS

Table of n, a(n) for n=0..104.

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

FORMULA

G.f.: x*(1 + 2*x + 5*x^2)/(1 - x^4).

E.g.f.: 2*exp(x) - exp(-x) - cos(x) - 2*sin(x).

a(n) = 2 - (-1)^n - cos(Pi*n/2) - 2*sin(Pi*n/2).

a(n+4) = a(n). - G. C. Greubel, Sep 26 2017

2*a(n) = (n mod 2) + (n mod 4)^2. - Bruno Berselli, Oct 18 2018

MATHEMATICA

CoefficientList[Series[x (1 + 2 x + 5 x^2)/(1 - x^4), {x, 0, 50}], x] (* G. C. Greubel, Sep 26 2017 *)

PadRight[{}, 120, {0, 1, 2, 5}] (* Harvey P. Dale, Apr 30 2022 *)

PROG

(PARI) x='x+O('x^50); Vec(x*(1+2*x+5*x^2)/(1-x^4)) \\ G. C. Greubel, Sep 26 2017

CROSSREFS

Sequence in context: A065452 A370541 A004598 * A336686 A371501 A118349

Adjacent sequences: A091083 A091084 A091085 * A091087 A091088 A091089

KEYWORD

nonn,easy

AUTHOR

Paul Barry, Dec 18 2003

STATUS

approved