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 A271986 #15 Sep 25 2020 11:15:22 %S A271986 0,299,5643,1357259,273624711,17832200896811,26748301350411, %T A271986 44580503598539,62412976762503,106993205379371,106993205384715, %U A271986 106993206736331,106993479003783 %N A271986 G_10(n), where G is the Goodstein function defined in A266201. %C A271986 a(17) = 1.926...*10^6103. - _Pontus von Brömssen_, Sep 25 2020 %H A271986 Pontus von Brömssen, <a href="/A271986/b271986.txt">Table of n, a(n) for n = 3..16</a> %H A271986 Wikipedia, <a href="https://en.wikipedia.org/wiki/Goodstein's_theorem">Goodstein's theorem</a> %o A271986 (Python) %o A271986 from sympy.ntheory.factor_ import digits %o A271986 def bump(n,b): %o A271986 s=digits(n,b)[1:] %o A271986 l=len(s) %o A271986 return sum(s[i]*(b+1)**bump(l-i-1,b) for i in range(l) if s[i]) %o A271986 def A271986(n): %o A271986 if n==3: return 0 %o A271986 for i in range(2,12): %o A271986 n=bump(n,i)-1 %o A271986 return n # _Pontus von Brömssen_, Sep 25 2020 %Y A271986 Cf. A056004: G_1(n); A057650: G_2(n); A059934: G_3(n); A059935: G_4(n); A059936: G_5(n); A271977: G_6(n); A271978: G_7(n); A271979: G_8(n); A271985: G_9(n); this sequence: G_10(n); A266201: G_n(n). %K A271986 nonn %O A271986 3,2 %A A271986 _Natan Arie Consigli_, May 01 2016 %E A271986 Incorrect program and terms removed by _Pontus von Brömssen_, Sep 25 2020