This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A103646 #25 Mar 07 2024 14:38:33
%S A103646 9,9,36,225,9,2304,1521,11025,49284,8649,576081,230400,3229209,
%T A103646 10478169,4639716,140778225,29192409,911556864,2153052801,1951430625,
%U A103646 33627490884,2586027609,249281516961,424895385600,715721076009,7848531119529
%N A103646 G.f.: 9*(3x+1)/(1+2x-6x^2-27x^3).
%C A103646 A floretion-generated sequence of squares. This sequence is related to several other sequences of squares.
%C A103646 Floretion Algebra Multiplication Program, FAMP Code: 4ibaseiseq[ x*(+ 'i + 'j + i' + j' + 'ii' + 'jj' + 'ij' + 'ji' + e) ] where x is the sum of all (16) floretion basis vectors.
%H A103646 Harvey P. Dale, <a href="/A103646/b103646.txt">Table of n, a(n) for n = 0..1000</a>
%H A103646 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (-2,6,27).
%F A103646 a(n+3) = -2a(n+2) + 6a(n+1) + 27a(n), a(0) = 9, a(1) = 9, a(2) = 36
%F A103646 a(n) = 9*A103644(n).
%F A103646 4*3^(n+1) = 2*A103644(n) + a(n) + A103645(n) = 11*A103644(n) + A103645(n).
%F A103646 a(n) = A110523(n+2)^2. - _R. J. Mathar_, Sep 11 2019
%t A103646 CoefficientList[ Series[9(3x + 1)/(1 + 2x - 6x^2 - 27x^3), {x, 0, 25}], x] (* _Robert G. Wilson v_, Feb 12 2005 *)
%t A103646 LinearRecurrence[{-2,6,27},{9,9,36},40] (* _Harvey P. Dale_, Mar 14 2016 *)
%Y A103646 Cf. A103644, A103645.
%K A103646 easy,nonn
%O A103646 0,1
%A A103646 _Creighton Dement_, Feb 12 2005
%E A103646 Corrected and extended by _Robert G. Wilson v_, Feb 12 2005