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 A078467 #14 Jun 13 2015 00:50:49 %S A078467 0,1,2,3,3,4,6,9,12,16,22,31,43,59,81,112,155,214,295,407,562,776, %T A078467 1071,1478,2040,2816,3887,5365,7405,10221,14108,19473,26878,37099, %U A078467 51207,70680,97558,134657,185864,256544,354102,488759,674623,931167,1285269 %N A078467 a(n) = a(n-1) + a(n-4); first four terms are 0,1,2,3. %H A078467 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 0, 1). %F A078467 a(n) = a(n-1) + a(n-4); a(0)=0, a(1)=1, a(2)=2, a(3)=3 %F A078467 a(n+1)=sum{k=0..n, binomial(n-k, floor(k/3))} - _Paul Barry_, Jul 06 2004 %F A078467 G.f.: x(1+x+x^2)/(1-x-x^4). a(n)=A003269(n)+A003269(n-1)+A003269(n-2). [From _R. J. Mathar_, Nov 25 2008] %e A078467 The sequence begins 0,1,2,3. a(5) = a(5-1) + a(5-4) = a(4)+a(1)= 3+0 =3. a(6) = a(6-1) + a(6-4) = a(5) + a(2) = 3+1 = 4. %t A078467 LinearRecurrence[{1,0,0,1},{0,1,2,3},50] (* _Harvey P. Dale_, Oct 08 2012 *) %Y A078467 Cf. A000045, A003269, A058278. %K A078467 nonn %O A078467 0,3 %A A078467 _Arran Fernandez_, Jan 02 2003