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 A302349 #20 Dec 05 2022 04:43:48 %S A302349 1,2,4,9, %T A302349 13407807929942597099574024998205846127479365820592393377723561443721764030073546976801874298166903427690031858186486050853753882811946569946433649006084096 %N A302349 a(n) = F_n(n,n), where F is the Clenshaw-Olver hyper-operation hierarchy. %C A302349 a(5) is too big to include. %C A302349 The Clenshaw Olver hyper-operation is a recursive function defined as follows: %C A302349 F_0(a,b) = b+1 %C A302349 F_n(a,0) = 0 %C A302349 F_n+1(a,b+1) = F_n(a, F_n+1(a, b)), for every nonnegative b and n. %H A302349 C. W. Clenshaw and F. W. J. Olver, <a href="https://doi.org/10.1145/62.322429">Beyond floating point</a>, Journal of the ACM. 31 (2) April 1984, pp. 319-328. %F A302349 F_1(a,b) = a+b; %F A302349 F_2(a,b) = ab; %F A302349 F_3(a,b) = a^b; %F A302349 F_4(a,b) = a[4](b-1). %F A302349 a[n]b is the square bracket notation for hyper-operation. See A054871 for details. %e A302349 F_0(0,0) = 0+1 = 1; %e A302349 F_1(1,1) = 1+1 = 2; %e A302349 F_2(2,2) = 2*2 = 4; %e A302349 F_3(a,b) = 3^3 = 9; %e A302349 F_4(a,b) = 4[4](4-1) = 4^4^4 = ... %Y A302349 Cf. A054871, A189896 (same instance using traditional hyper-operation hierarchy). %K A302349 nonn %O A302349 0,2 %A A302349 _Natan Arie Consigli_, Apr 05 2018