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A007893 A Kutz sequence. 1
1, 4, 9, 16, 1, 4, 9, 16, 25, 4, 9, 16, 25, 36, 9, 16, 25, 36, 49, 16, 25, 36, 49, 64, 25, 36, 49, 64, 81, 36, 49, 64, 81, 100, 49, 64, 81, 100, 121, 64, 81, 100, 121, 144, 81, 100, 121, 144, 169, 100, 121, 144, 169, 196, 121, 144, 169, 196, 225, 144, 169, 196 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

R. E. Kutz, Two unusual sequences, Two-Year College Mathematics Journal, 12 (1981), 316-319.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,2,-2,0,0,0,-1,1).

FORMULA

The pattern is obvious!

a(n) = (n - 4*floor(n/5))^2. - Michael Somos, Jun 01 1999

G.f.: x*(1+3*x+5*x^2+7*x^3-15*x^4+x^5-x^6-3*x^7-5*x^8+9*x^9) / ((1-x)^3*(1+x+x^2+x^3+x^4)^2). - Colin Barker, Aug 05 2016

MATHEMATICA

Table[(n - 4*Floor[n/5])^2, {n, 60}] (* Arkadiusz Wesolowski, Sep 29 2011 *)

PROG

(MAGMA) [(n-4*Floor(n/5))^2: n in [1..60]]; // Vincenzo Librandi, Sep 30 2011

(PARI) Vec(x*(1+3*x+5*x^2+7*x^3-15*x^4+x^5-x^6-3*x^7-5*x^8+9*x^9)/((1-x)^3*(1+x+x^2+x^3+x^4)^2) + O(x^60)) \\ Colin Barker, Aug 05 2016

CROSSREFS

Sequence in context: A106548 A106546 A276191 * A070446 A258682 A070445

Adjacent sequences:  A007890 A007891 A007892 * A007894 A007895 A007896

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 20 06:59 EDT 2021. Contains 343125 sequences. (Running on oeis4.)