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A028869 Squares of primes with digits in descending order. 3
4, 9, 841, 961 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 8 15:37 EDT 2020. Contains 333314 sequences. (Running on oeis4.)