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A101207 For each prime power n, a(n) is the number of positive integers that have n as their greatest prime power. 2

%I #9 Jun 25 2022 20:02:16

%S 1,1,2,2,6,0,12,8,16,0,48,0,96,0,0,48,240,0,480,0,0,0,960,0,960,0,960,

%T 0,3840,0,7680,3072,0,0,0,0,18432,0,0,0,36864,0,73728,0,0,0,147456,0,

%U 147456,0,0,0,442368,0,0,0,0,0,884736,0,1769472,0,0,589824

%N For each prime power n, a(n) is the number of positive integers that have n as their greatest prime power.

%C a(n) is the number of occurrences of n in A034699.

%F a(1) = 1; a(p^k) = prod_{q <= p^k, q prime} { ceiling(k log p / log q) } / k when p prime, k >= 1, a(n) = 0 otherwise

%e a(4) = 2 since only 4 and 12 have 4 as their greatest prime power - all other multiples of 4 are divisible by 8, 9, or some prime >= 5.

%Y Cf. A034699.

%K nonn,easy

%O 1,3

%A _Hugo van der Sanden_, Dec 13 2004

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