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 A329288 #28 Mar 19 2020 13:47:58 %S A329288 1,1,2,1,2,3,1,2,3,4,1,2,3,5,5,1,2,3,5,5,6,1,2,3,5,5,7,7,1,2,3,5,5,7, %T A329288 7,8,1,2,3,5,5,7,7,11,9,1,2,3,5,5,7,7,11,11,10,1,2,3,5,5,7,7,11,11,11, %U A329288 11,1,2,3,5,5,7,7,11,11,11,11,12 %N A329288 Table T(n,k) read by antidiagonals: T(n,k) = f(T(n,k)) starting with T(n,1)=n, where f(x) = x - 1 + x/gpf(x), that is, f(x) = A269304(x)-2. %C A329288 If p=T(n,k0) is prime, then T(n,k) = p - 1 + p/p = p for k > k0. Thus, primes are fixed points of this map. The number of different terms in the n-th row is given by A330437. %e A329288 Table begins: %e A329288 1, 1, 1, 1, 1, ... %e A329288 2, 2, 2, 2, 2, ... %e A329288 3, 3, 3, 3, 3, ... %e A329288 4, 5, 5, 5, 5, ... %e A329288 5, 5, 5, 5, 5, ... %e A329288 6, 7, 7, 7, 7, ... %e A329288 7, 7, 7, 7, 7, ... %e A329288 8, 11, 11, 11, 11, ... %e A329288 9, 11, 11, 11, 11, ... %e A329288 10, 11, 11, 11, 11, ... %e A329288 11, 11, 11, 11, 11, ... %e A329288 12, 15, 17, 17, 17, ... %e A329288 13, 13, 13, 13, 13, ... %e A329288 14, 15, 17, 17, 17, ... %t A329288 Clear[f,it,order,seq]; f[n_]:=f[n]=n-1+n/FactorInteger[n][[-1]][[1]]; it[k_,n_]:=it[k,n]=f[it[k,n-1]]; it[k_,1]=k; SetAttributes[f,Listable]; SetAttributes[it,Listable]; it[#,Range[10]]&/@Range[800] %Y A329288 Cf. A006530 (greatest prime factor), A269304. %K A329288 nonn,tabl %O A329288 1,3 %A A329288 _Elijah Beregovsky_, Feb 16 2020