A028869 Squares of primes with digits in nonascending order.

4, 9, 841, 961

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base
• hard
• more

Comments

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

Examples

			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.
		

Crossrefs

Cf. A028868, A028865, A028866.

Programs

Mathematica

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

Extensions

Offset changed by Altug Alkan, Sep 09 2016

Name clarified by Jon E. Schoenfield, Oct 27 2023