6874560domain: NAppears in sequencesT(2n-1,n), array T as in A054144.at n=10A054149Numbers which in at least two ways are the product of two distinct numbers with the same digits (leading zeros are forbidden).at n=29A077760a(n) = n/(Sum_{k=1..n} 1/phi(A341813(n)*k)).at n=30A341814