[seqfan] Re: Squares of digits of primes

[israel at math.ubc.ca]

The following Maple program finds those p in the first 100000 primes
such that sqrt(p - ssd(p)) is a prime, where ssd(p) is the sum of the
squares of the digits of p.

> ssd:= n->add(d^2,d=convert(n,base,10));
  S:= select(t -> type(sqrt(t - ssd(t)),prime), 
[seq(ithprime(j),j=1..10^5)]);

S := [11, 2903, 3533, 3803, 5197, 9533, 18973, 24763, 37321, 73561, 96953, 
113621, 124777, 129097, 134837, 139241, 398341, 830003, 1100509]

Cheers,
Robert Israel

On Aug 8 2013, Victor Miller wrote:

>I'm forwarding this to the list from Underwood Dudley:
>
>Underwood Dudley <ddunx46135 at yahoo.com>
>
>
>
>
>     A correspondent of mine, Will Gosnell, has noticed that if the sum of
>the squares of the digits of the prime 18973 is subtracted from it, the
>result is the square of 137. For the prime 73561, the result is the square
>of 271.
>     I thought that someone more skilled with computers than I might like
>to extend the list. It would create a new entry for the Encyclopaedia of
>Integer Sequences.
>
>     Woody Dudley
>
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