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 A106223 #7 Mar 13 2015 19:18:33
%S A106223 1,1,-2,6,-21,80,-320,1326,-5637,24434,-107541,479192,-2157027,
%T A106223 9792618,-44780207,206053429,-953296364,4431418833,-20686477329,
%U A106223 96930426941,-455717114981,2149060994827,-10162417338993,48176297258115,-228910042632050,1089957826522693,-5199911987465160
%N A106223 Self-convolution 5th power equals A106222, which consists entirely of digits {0,1,2,3,4} after the initial terms {1,5}.
%F A106223 Limit a(n+1)/a(n) = -5.001596426773442826534115368782519...
%e A106223 A(x) = 1 + x - 2*x^2 + 6*x^3 - 21*x^4 + 80*x^5 - 320*x^6 +-...
%e A106223 A(x)^5 = 1 + 5*x + x^5 + 3*x^10 + x^15 + 4*x^20 + x^35 +...
%e A106223 A106222 = {1,5,0,0,0,1,0,0,0,0,3,0,0,0,0,1,0,0,0,0,4,...}.
%o A106223 (PARI) {a(n)=local(A=1+5*x);if(n==0,1, for(j=1,n, for(k=0,4,t=polcoeff((A+k*x^j+x*O(x^j))^(1/5),j); if(denominator(t)==1,A=A+k*x^j;break))); return(polcoeff((A+x*O(x^n))^(1/5),n)))}
%Y A106223 Cf. A106222, A106219, A106221, A106225.
%K A106223 sign,base
%O A106223 0,3
%A A106223 _Paul D. Hanna_, May 01 2005