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 A116521 #16 Jun 28 2017 21:29:39 %S A116521 0,0,0,1,5,17,51,148,429,1250,3655,10701,31336,91752,268623,786414, %T A116521 2302262,6739984,19731685,57765711,169112717,495088023,1449400960, %U A116521 4243211207,12422263776,36366946961,106466490879,311687250156 %N A116521 Binomial transform of tetranacci sequence A000078. %C A116521 See also A115390, the binomial transform of tribonacci sequence A000073. Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4), with a(0) = a(1) = a(2) = 0, a(3) = 1. %H A116521 G. C. Greubel, <a href="/A116521/b116521.txt">Table of n, a(n) for n = 0..1000</a> %H A116521 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,6,-1). %F A116521 a(n) = Sum_{k=0..n} C(n,k) * A000078(k). %F A116521 G.f.: x^3/(1-5*x+8*x^2-6*x^3+x^4). - _Emeric Deutsch_, Apr 09 2006 %F A116521 a(n) = 5*a(n-1) - 8*a(n-2) + 6*a(n-3) - a(n-4). - _G. C. Greubel_, Nov 03 2016 %e A116521 Table shows the tetranacci numbers multiplied into rows of Pascal's triangle. %e A116521 1*0 = 0. %e A116521 1*0 + 1*0 = 0. %e A116521 1*0 + 2*0 + 1*0 = 0. %e A116521 1*0 + 3*0 + 3*0 + 1* 1 = 1. %e A116521 1*0 + 4*0 + 6*0 + 4*1 + 1*1 = 5. %e A116521 1*0 + 5*0 + 10*0 + 10*1 + 5*1 + 1*2 = 17. %p A116521 t[0]:=0: t[1]:=0: t[2]:=0: t[3]:=1: for n from 4 to 35 do t[n]:=t[n-1]+t[n-2]+t[n-3]+t[n-4] od: seq(add(binomial(n,k)*t[k],k=0..n),n=0..30); # end of first Maple program %p A116521 G:=x^3/(1-5*x+8*x^2-6*x^3+x^4): Gser:=series(G,x=0,33): seq(coeff(Gser,x,n),n=0..30); # _Emeric Deutsch_, Apr 09 2006 %t A116521 LinearRecurrence[{5,-8,6,-1}, {0,0,0,1}, 25] (* _G. C. Greubel_, Nov 03 2016 *) %o A116521 (PARI) a(n)=([0,1,0,0; 0,0,1,0; 0,0,0,1; -1,6,-8,5]^n*[0;0;0;1])[1,1] \\ _Charles R Greathouse IV_, Jun 28 2017 %Y A116521 Cf. A000073, A000078, A115390. %K A116521 easy,nonn %O A116521 0,5 %A A116521 _Jonathan Vos Post_, Mar 10 2006 %E A116521 Definition corrected by _Franklin T. Adams-Watters_, Mar 13 2006 %E A116521 More terms from _Emeric Deutsch_, Apr 09 2006