A333969 Squares of terms are the intersection of A025487 and A217584.

1, 12, 60, 1260, 13860, 180180, 277200, 900900, 3628800, 15315300, 28828800, 38880000, 290990700, 373248000, 428828400, 2036934900, 2477260800, 3632428800, 6692786100, 8147739600, 13335840000, 15682867200, 15925248000, 20956320000, 46849502700, 61751289600, 65181916800, 68976230400

Offset: 1

Author

David A. Corneth, May 30 2020

Keywords

• nonn

Comments

As all terms in A217584 are squares so these list the square roots.

Also: Numbers k such that k^2 is the least positive integer having its prime signature and d(k^4)/d(k^2) is an integer.

Examples

			12 is in the sequence as 12^2 = 144 and 144^2 has 45 divisors and 144 has 15 divisors and 45/15 = 3 is an integer and 12 is in A025487 and so is 144.
		

Links

• David A. Corneth, Table of n, a(n) for n = 1..3393

Crossrefs

Cf. A025487, A217584.