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Highest common factor of successive highly composite numbers (1), A002182.
6

%I #22 Sep 29 2015 09:10:32

%S 1,2,2,6,12,12,12,12,60,60,60,120,360,120,420,420,840,2520,2520,2520,

%T 5040,5040,5040,2520,2520,5040,5040,27720,27720,55440,55440,55440,

%U 55440,166320,55440,110880,55440,360360,360360

%N Highest common factor of successive highly composite numbers (1), A002182.

%C Not the same as the first differences of A002182. The latter are given by A262501, which differs from this sequence for the first time at n=25, where A262501(25) = 17640, while here the 25th term a(26) is 2520. The sequences differ next time at positions n = 52, 53, 54, 64, 67, 82, 83, 84, 85, 86, 87, 88, 90, 91, 96, 100, 106, ... (when one-based indexing as in A262501 is used). - _Antti Karttunen_, Sep 24 2015

%H Antti Karttunen, <a href="/A054481/b054481.txt">Table of n, a(n) for n = 2..1000</a> (computed from the b-file of A002182 provided by _T. D. Noe_)

%F a(n) = GCD(A002182(n-1), A002182(n)) = A002182(n)/A054483(n) = A002182(n-1)/A054482(n).

%e a(7)=12 because A002182(7)=36, A002182(6)=24 and GCD(36,24)=12.

%Y Cf. A002182, A054482, A054483, A262501.

%K easy,nonn

%O 2,2

%A _Henry Bottomley_, Mar 31 2000

%E Erroneous comment (wrong interpretation) removed by _Antti Karttunen_, Sep 25 2015