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 A145608 #19 Jan 03 2024 23:46:02
%S A145608 0,3,27,216,1704,13419,105651,831792,6548688,51557715,405913035,
%T A145608 3195746568,25160059512,198084729531,1559517776739,12278057484384,
%U A145608 96664942098336,761041479302307,5991666892320123,47172293659258680,371386682381749320,2923921165394735883,23019982640776137747
%N A145608 Numbers a(n)=k such that (1/3)*(5*(2k+1)^2-2) is A057080(n)^2.
%H A145608 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9,-9,1).
%F A145608 a(n+2) = 8*a(n+1) - a(n) + 3.
%F A145608 a(n) = (A070997(n)-1)/2 = 3*A076765(n-1). - _R. J. Mathar_, Oct 16 2008
%F A145608 G.f.: -3*x / ( (x-1)*(x^2-8*x+1) ). - _R. J. Mathar_, Nov 27 2011
%F A145608 a(n) = 9*a(n-1) - 9*a(n-2) + a(n-3); a(0)=0, a(1)=3, a(2)=27. - _Harvey P. Dale_, May 06 2013
%t A145608 RecurrenceTable[{a[0]==0,a[1]==3,a[n]==8a[n-1]-a[n-2]+3},a,{n,30}] (* or *) LinearRecurrence[{9,-9,1},{0,3,27},30] (* _Harvey P. Dale_, May 06 2013 *)
%Y A145608 Cf. A057080, A131571, A145607.
%K A145608 easy,nonn
%O A145608 0,2
%A A145608 _Richard Choulet_, Oct 14 2008
%E A145608 Made definition and sequence consistent. Changed offset to 0. - _R. J. Mathar_, Oct 16 2008