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 A104312 #4 Mar 30 2012 17:22:35
%S A104312 3,31,101,3823,2266366724843687556556015073508073201681
%N A104312 Prime coefficient of x^n in (x^3+x^2+x+1)^n for n in A104311.
%C A104312 a(6), which corresponds to n=649, is too large to include.
%t A104312 f=1; Do[f=Expand[f*(x^3+x^2+x+1)]; s=Coefficient[f, x, n]; If[PrimeQ[s], Print[{n, s}]], {n, 1000}]
%Y A104312 Cf. A005725 (quadrinomial coefficients), A104314 (nontrivial prime pentanomial coefficients).
%K A104312 nonn
%O A104312 1,1
%A A104312 _T. D. Noe_, Mar 01 2005