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Number of positive integers <= 10^n that are divisible by no prime exceeding 13.
4

%I #10 Nov 14 2019 14:43:46

%S 1,10,62,242,733,1848,4106,8289,15519,27365,45914,73908,114831,173077,

%T 254065,364385,511985,706293,958460,1281500,1690506,2202871,2838489,

%U 3620013,4573071,5726533,7112760,8767880,10732089,13049906,15770500,18948010,22641849,26917042,31844560

%N Number of positive integers <= 10^n that are divisible by no prime exceeding 13.

%t n = 10; t = Select[ Flatten[ Table[13^f*Select[ Flatten[ Table[11^e*Select[ Flatten[ Table[7^d*Select[ Flatten[ Table[5^c*Select[ Flatten[ Table[2^a*3^b, {a, 0, n*Log[2, 10]}, {b, 0, n*Log[3, 10]}]], # <= 10^n &], {c, 0, n*Log[5, 10]}]], # <= 10^n &], {d, 0, n*Log[7, 10]}]], # <= 10^n &], {e, 0, n*Log[11, 10]}]], # <= 10^n &], {f, 0, n*Log[13, 10]}]], # <= 10^n &]; Table[ Length[ Select[t, # <= 10^n &]], {n, 0, 10}];

%Y Row 6 of A253635.

%Y Cf. A011557, A080197.

%K nonn

%O 0,2

%A _Robert G. Wilson v_, May 27 2005

%E a(21)-a(34) from _Daniel Suteu_, Nov 14 2019