is a Sastry number if concatenated with
For example, 183 is a Sastry number because 183184 is the square of 428.
F.Luca has proved that there exists a Sastry number with digits if and only if is not a prime number, a thing that happen only for and for .
The first Sastry numbers are
183, 328, 528, 715, 6099, 13224, 40495, 106755, 453288, 2066115, 2975208, 22145328, 28027683 more terms
Pictorial representation of remainders (mod 2, 3, ...,11) frequency. For a table of values and more details click here
A graph displaying how many Sastry numbers are multiples of the primes p
from 2 to 71. In black the ideal line 1/p