Array read by downward antidiagonals: T(k,n) is the least number that has k prime factors (counted with multiplicity) and is the concatenation of n primes, or -1 if there is no such number.
A374376
Array read by downward antidiagonals: T(k,n) is the least number that has k prime factors (counted with multiplicity) and is the concatenation of n primes, or -1 if there is no such number.
Terms
- a(0) =2a(1) =23a(2) =-1a(3) =223a(4) =22a(5) =-1a(6) =2237a(7) =235a(8) =27a(9) =-1a(10) =22273a(11) =2227a(12) =222a(13) =132a(14) =-1a(15) =222323a(16) =22223a(17) =2222a(18) =225a(19) =32a(20) =-1a(21) =2222273a(22) =222223a(23) =22222a(24) =2223a(25) =252a(26) =729a(27) =-1a(28) =22222223a(29) =2222557
External references
- oeis: A374376