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Where records occur in A152235.
2

%I #17 Apr 29 2023 12:06:36

%S 1,2,4,12,48,144,576,720,2880,25920,129600,414720,907200,14515200,

%T 58060800,130636800,522547200,3265920000,13063680000,22861440000,

%U 91445760000,251475840000,1005903360000,16094453760000,64377815040000,81478172160000,1030045040640000

%N Where records occur in A152235.

%H Amiram Eldar, <a href="/A152453/b152453.txt">Table of n, a(n) for n = 1..87</a>

%e First few terms of A152235 are 1, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 6, so a(1) to a(4) are 1, 2, 4, 12.

%o (Magma) W:=[]; r:=0; for n in [1..1300000] do a:=&*PrimeDivisors(NumberOfDivisors(n)); if r lt a then r:=a; Append(~W,n); end if; end for; print W;

%Y Cf. A152235 (largest squarefree number dividing the number of divisors of n), A152452 (records in A152235), A007947 (largest squarefree number dividing n).

%Y Subsequence of A025487.

%K nonn

%O 1,2

%A _Klaus Brockhaus_, Dec 04 2008

%E a(15)-a(20) from _Donovan Johnson_, Jul 30 2011

%E More terms from _Amiram Eldar_, Sep 01 2019