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 A083949 #11 Oct 31 2013 12:17:23 %S A083949 1,9,9,3,9,9,3,9,9,1,9,9,6,9,9,6,9,9,9,9,9,6,9,9,6,9,9,9,9,9,3,9,9,3, %T A083949 9,9,2,9,9,6,9,9,6,9,9,7,9,9,9,9,9,9,9,9,5,9,9,9,9,9,9,9,9,3,9,9,6,9, %U A083949 9,6,9,9,5,9,9,9,9,9,9,9,9,3,9,9,9,9,9,9,9,9,1,9,9,6,9,9,6,9,9,7,9,9,6,9,9 %N A083949 Integer coefficients of A(x), where 1<=a(n)<=9, such that A(x)^(1/9) consists entirely of integer coefficients. %C A083949 More generally, the sequence, "integer coefficients of A(x), where 1<=a(n)<=m, such that A(x)^(1/m) consists entirely of integer coefficients", appears to have a unique solution for all m. Are these sequences periodic? %H A083949 Robert G. Wilson v, <a href="/A083949/b083949.txt">Table of n, a(n) for n = 0..3000</a>. %t A083949 a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/9), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 104}] (* _Robert G. Wilson v_ *) %Y A083949 Cf. A083952, A083953, A083954, A083955, A083956, A083947, A083948, A083950. %K A083949 nonn %O A083949 0,2 %A A083949 _Paul D. Hanna_, May 09 2003 %E A083949 More terms from _Robert G. Wilson v_, Jul 26 2005