A106629 Number of positive integers <= 10^n that are divisible by no prime exceeding 13.
1, 10, 62, 242, 733, 1848, 4106, 8289, 15519, 27365, 45914, 73908, 114831, 173077, 254065, 364385, 511985, 706293, 958460, 1281500, 1690506, 2202871, 2838489, 3620013, 4573071, 5726533, 7112760, 8767880, 10732089, 13049906, 15770500, 18948010, 22641849, 26917042, 31844560
Offset: 0
Keywords
Programs
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Mathematica
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}];
Extensions
a(21)-a(34) from Daniel Suteu, Nov 14 2019