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%I #13 Jul 31 2015 12:52:30
%S 1,4,9,16,30,59,114,219,422,814,1569,3024,5829,11236,21658,41747,
%T 80470,155111,298986,576314,1110881,2141292,4127473,7955960,15335606,
%U 29560331,56979370,109831267,211706574,408077542,786594753,1516210136,2922589005
%N Tetranacci numbers starting with first four squares.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1, 1, 1).
%F a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4).
%F G.f.: -x*(1+x)*(2*x^2+2*x+1)/(-1+x+x^2+x^3+x^4). a(n)=2*A000078(n+3)+2*A000078(n)-A001631(n+1). [_R. J. Mathar_, Apr 20 2009]
%t a[1] = 1; a[2] = 4; a[3] = 9; a[4] = 16; a[n_] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] + a[n - 4]; Table[ a[n], {n, 33}] (* _Robert G. Wilson v_ *)
%t LinearRecurrence[{1,1,1,1},Range[4]^2,40] (* _Harvey P. Dale_, Oct 16 2012 *)
%Y Cf. A086192.
%K nonn
%O 1,2
%A Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), May 11 2004
%E More terms from _Robert G. Wilson v_ and _Labos Elemer_, May 12 2004, May 11 2004
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