A175752 Numbers with 45 divisors.
3600, 7056, 8100, 15876, 17424, 19600, 20736, 22500, 24336, 39204, 41616, 48400, 51984, 54756, 67600, 76176, 86436, 93636, 94864, 99225, 104976, 115600, 116964, 121104, 122500, 132496, 138384, 144400, 147456, 160000, 171396, 197136
Offset: 1
Keywords
Links
- T. D. Noe, Table of n, a(n) for n = 1..1000
- OEIS Wiki, Index entries for number of divisors
Programs
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Mathematica
Select[Range[400000],DivisorSigma[0,#]==45&] (* Vladimir Joseph Stephan Orlovsky, May 06 2011 *)
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PARI
is(n)=numdiv(n)==45 \\ Charles R Greathouse IV, Jun 19 2016
Formula
A000005(a(n)) = 45.
Sum_{n>=1} 1/a(n) = (P(2)^2*P(4) - P(4)^2)/2 - P(2)*P(6) + P(8) + P(2)*P(14) - P(16) + P(4)*P(8) - P(12) + P(44) = 0.00133023..., where P is the prime zeta function. - Amiram Eldar, Jul 03 2022
Comments