A017102 - OEIS

A017102

a(n) = (8n + 3)^2.

9, 121, 361, 729, 1225, 1849, 2601, 3481, 4489, 5625, 6889, 8281, 9801, 11449, 13225, 15129, 17161, 19321, 21609, 24025, 26569, 29241, 32041, 34969, 38025, 41209, 44521, 47961, 51529, 55225, 59049, 63001, 67081, 71289, 75625, 80089, 84681

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OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..2000

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

FORMULA

a(0)=9, a(1)=121, a(2)=361, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Feb 23 2014

Sum_{n>=0} 1/a(n) = psi'(3/8)/64 = 0.127527775511898... - R. J. Mathar, May 07 2024

MATHEMATICA

Table[(8n + 3)^2, {n, 0, 40}] (* Stefan Steinerberger, Apr 08 2006 *)

LinearRecurrence[{3, -3, 1}, {9, 121, 361}, 40] (* Harvey P. Dale, Feb 23 2014 *)

PROG

(Magma) [(8*n+3)^2: n in [0..40]]; // Vincenzo Librandi, Jun 07 2011

(PARI) a(n)=(8*n+3)^2 \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Sequence in context: A234320 A157930 A259836 * A167722 A103930 A302941

Adjacent sequences: A017099 A017100 A017101 * A017103 A017104 A017105

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Stefan Steinerberger, Apr 08 2006

STATUS

approved