277241401domain: NAppears in sequencesCarmichael numbers of the form n*(2*n - 1)*(p*n - p + 1)*(2*p*n - 2*p + 1), where p is odd, p from 3 to 23.at n=4A212882Carmichael numbers n such that n-1 is not a practical number.at n=23A265827