

A028869


Squares of primes with digits in descending order.


3




OFFSET

1,1


COMMENTS

No other solutions below 4 * 10^18 (probably finite).  Dec 15 1999


LINKS

Table of n, a(n) for n=1..4.


EXAMPLE

961 = 31^2 is in the sequence since its digits (9, 6, 1) are in descending order.
1369 = 37^2 is not in the sequence, since its digits in descending order are: 9, 6, 3, 1.


MATHEMATICA

Select[Prime[Range[100]]^2, IntegerDigits[#] == Sort[IntegerDigits[#], Less] &] (* Alonso del Arte, Aug 12 2016 *)


CROSSREFS

Cf. A028868, A028865, A028866.
Sequence in context: A027522 A330580 A254959 * A179935 A073172 A168139
Adjacent sequences: A028866 A028867 A028868 * A028870 A028871 A028872


KEYWORD

nonn,base,hard,more


AUTHOR

Patrick De Geest


EXTENSIONS

Offset changed by Altug Alkan, Sep 09 2016


STATUS

approved



