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 A211378 #22 Feb 16 2025 08:33:17 %S A211378 19,7625597484990, %T A211378 13407807929942597099574024998205846127479365820592393377723561443721764030073546976801874298166903427690031858186486050853753882811946569946433649006084099 %N A211378 Goodstein sequence starting with 19. %C A211378 To calculate a(n), write a(n-1) in the hereditary representation base n+1, then bump the base to n+2, then subtract 1. %H A211378 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GoodsteinSequence.html">Goodstein Sequence</a> %H A211378 Wikipedia, <a href="http://en.wikipedia.org/wiki/Goodstein's_theorem">Goodstein's Theorem</a> %H A211378 Reinhard Zumkeller, <a href="/A211378/a211378.hs.txt">Haskell programs for Goodstein sequences</a> %e A211378 The first terms are (see Wikipedia): %e A211378 a(0) = 2^2^2 + 2^1 + 2^0 = 19 %e A211378 a(1) = 3^3^3 + 3^1 + 3^0 - 1 = 7625597484990 %e A211378 a(2) = 4^4^4 + 4^1 - 1 (155 digits) %e A211378 a(3) = 5^5^5 + 3 - 1 (2185 digits) %e A211378 a(4) = 6^6^6 + 2 - 1 (36306 digits) %e A211378 a(5) = 7^7^7 + 1 - 1 (695975 digits) %e A211378 a(6) = 8^8^8 - 1 (15151336 digits). %o A211378 (Haskell) -- See Link %Y A211378 Cf. A215409 (start=3), A056193 (start=4), A222117 (start=15), A059933 (start=16). %K A211378 nonn,fini %O A211378 0,1 %A A211378 _Reinhard Zumkeller_, Feb 13 2013 %E A211378 Offset changed to 0 by _Nicholas Matteo_, Aug 21 2019