cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A333326 Odd numbers k such that k is the product of 2 numbers greater than one, in two or more ways.

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%I A333326 #32 Mar 19 2020 11:21:43
%S A333326 45,63,75,81,99,105,117,135,147,153,165,171,175,189,195,207,225,231,
%T A333326 243,245,255,261,273,275,279,285,297,315,325,333,345,351,357,363,369,
%U A333326 375,385,387,399,405,423,425,429,435,441,455,459,465,475
%N A333326 Odd numbers k such that k is the product of 2 numbers greater than one, in two or more ways.
%C A333326 Odd numbers that are not 1, a prime, the square or cube of a prime, or the product of two primes. - _Robert Israel_, Mar 19 2020
%H A333326 Robert Israel, <a href="/A333326/b333326.txt">Table of n, a(n) for n = 1..10000</a>
%e A333326 For n=2 the a(2) = 63 because 63 = 3 * 21 and 7 * 9.
%p A333326 select(t -> numtheory:-tau(t) >= 5, [seq(i,i=3..1000,2)]); # _Robert Israel_, Mar 19 2020
%t A333326 Select[2 * Range[250] + 1, DivisorSigma[0, #] > 4 &] (* _Amiram Eldar_, Mar 15 2020 *)
%o A333326 (PARI) forcomposite(n=4, 475, if(n%2 == 0, next()); if(numdiv(n) >= 5, print1(n,", "))); \\ _Joerg Arndt_, Mar 15 2020
%Y A333326 Cf. A005408, A058080, A226025.
%K A333326 nonn
%O A333326 1,1
%A A333326 _Dimitris Valianatos_, Mar 15 2020