A380034 - OEIS

%I #5 Jan 15 2025 08:43:31

%S 1,2,3,4,5,6,7,9,12,13,14,15,17,21,28,31,35,41,42,45,51,54,60,61,67,

%T 75,89,90,111,118,133,147,155,163,176,185,186,195,205,231,246,277,307,

%U 323,343,368,369,377,383,411,429,455,471,479,490,502,545,565,567,627

%N Records in A380032.

%C See comments in A380032.

%H Michael De Vlieger, <a href="/A380034/b380034.txt">Table of n, a(n) for n = 1..66</a>

%t (* Load function f at A025487 *)

%t r = 0;

%t s = Select[Union@ Flatten@ f[8][[3 ;; -1]], Not @* SquareFreeQ];

%t nn = Length[s]; Print[nn];

%t Reap[Monitor[

%t   Do[k = s[[i]];

%t     If[# > r, r = #; Sow[r]] &@

%t       Count[Transpose@ {#, k/#} &@ #[[2 ;; Ceiling[Length[#]/2]]] &@ Divisors[k],

%t         _?((m = GCD @@ {##};

%t           And[! MemberQ[{1, #2}, m],

%t           m == #1,

%t           ! Divisible[#1, rad[#2]]]) & @@ # &)], {i, nn}], i] ][[-1, 1]]

%Y Cf. A380032, A380033.

%K nonn

%O 1,2

%A _Michael De Vlieger_, Jan 11 2025