Numbers n such that sopfr(n)/spf(n) is a semiprime and sopfr(n)/lpf(n) is a semiprime, where sopfr(n) = A001414(n) is sum of primes dividing n (with repetition), spf(n) and lpf(n) are smallest and largest primes dividing n, respectively. Also, spf(n)!=lpf(n).
A085718
Numbers n such that sopfr(n)/spf(n) is a semiprime and sopfr(n)/lpf(n) is a semiprime, where sopfr(n) = A001414(n) is sum of primes dividing n (with repetition), spf(n) and lpf(n) are smallest and largest primes dividing n, respectively. Also, spf(n)!=lpf(n).
Terms
- a(0) =72a(1) =576a(2) =648a(3) =750a(4) =800a(5) =900a(6) =960a(7) =1080a(8) =3430a(9) =4116a(10) =4900a(11) =5880a(12) =6272a(13) =7000a(14) =7056a(15) =7938a(16) =8400a(17) =8960a(18) =9450a(19) =10080a(20) =10752a(21) =11340a(22) =12096a(23) =13608a(24) =18750a(25) =20000a(26) =22500a(27) =24000a(28) =25600a(29) =27000
External references
- oeis: A085718