cp's OEIS Frontend

Or numbers n >= 16 having a divisor t^2 > 1, where t=k/m, 1 <= m < k, such that n == n/t^2 (mod 7).

Or positive numbers n such that if n == 0 (mod 7), then n is divisible by 7^3 or by the square of some other prime; otherwise n is divisible by k^2, such that there is a k_1, 0 < k_1 < k such that k_1^2 == k^2 (mod 7) (or, according to the comment in A130290, n is divisible by some k^2 >= 16).

For a generalization, see the seqfan list from Jun 13 (correction Jun 14) 2016.

Or numbers n >= 36 having a divisor t^2 > 1, where t=k/m, 1 <= m < k, such that n == n/t^2 (mod 11).

Or positive numbers n such that if n == 0 (mod 11), then n is divisible by 11^3 or by the square of some other prime; otherwise n is divisible by k^2, such that there is a k_1, 0 < k_1 < k with k_1^2 == k^2 (mod 11) (or, according to the comment in A130290, n is divisible by some k^2 >= 36).

For a generalization, see the Sequence Fans mailing list for Jun 13 2016 (correction Jun 14 2016).

From David A. Corneth, Jun 26 2016: (Start)

If k is a term then m * k is a term for m > 0. Hence closed under multiplication. For k > 11, k^2 is in the sequence. So k^t is as well for t > 2.

Summarizing, k is a term iff

- k is of the form k^2 for floor(11/2) < k except k = 11.

- k is of the form 11 * p^2 for p < floor(11/2)

- of the form k * t for k of one of the forms above and integer t > 0. (End)