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A152020 Denominator of 8/(9n^2) divided by 9. 1
1, 1, 9, 2, 25, 9, 49, 8, 81, 25, 121, 18, 169, 49, 225, 32, 289, 81, 361, 50, 441, 121, 529, 72, 625, 169, 729, 98, 841, 225, 961, 128, 1089, 289, 1225, 162, 1369, 361, 1521, 200, 1681, 441, 1849, 242, 2025, 529, 2209, 288, 2401, 625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..50.

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 3, 0, 0, 0, -3, 0, 0, 0, 1).

FORMULA

a(n) = A152018(n)/9.

a(1)=1, a(2)=1, a(3)=9, a(4)=2, a(5)=25, a(6)=9, a(7)=49, a(8)=8, a(9)=81, a(10)=25, a(11)=121, a(12)=18, a(n)=3*a(n-4)-3*a(n-8)+a(n-12). - Harvey P. Dale, Aug 25 2013

Conjecture: a(n) = denominator((n-2)^3/n^2). - Andres Cicuttin, Sep 19 2017

a(n) = n^2/gcd(n^2, 8). - Andrew Howroyd, Jul 25 2018

MATHEMATICA

Denominator[8/(9*Range[50]^2)]/9 (* or *) LinearRecurrence[{0, 0, 0, 3, 0, 0, 0, -3, 0, 0, 0, 1}, {1, 1, 9, 2, 25, 9, 49, 8, 81,  25, 121, 18}, 50] (* Harvey P. Dale, Aug 25 2013 *)

PROG

(PARI) a(n) = denominator(8/(9*n^2))/9 \\ Michel Marcus, Jun 01 2013

CROSSREFS

Sequence in context: A040080 A272033 A098289 * A055516 A248314 A174837

Adjacent sequences:  A152017 A152018 A152019 * A152021 A152022 A152023

KEYWORD

nonn,mult

AUTHOR

Paul Curtz, Nov 20 2008

EXTENSIONS

More terms from Michel Marcus, Jun 01 2013

Keyword:mult added by Andrew Howroyd, Jul 25 2018

STATUS

approved

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Last modified August 1 17:16 EDT 2021. Contains 346402 sequences. (Running on oeis4.)