A028866 Squares of primes having digits in nondecreasing order.

4, 9, 25, 49, 169, 289, 1369, 4489, 6889, 11449, 27889, 113569, 134689, 146689, 344569, 2778889, 27777888889, 111113555569, 111133556689, 111333666889, 113344668889, 444444888889, 1111133355666889, 1133444466888889

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base
• less

Comments

What is the rate of growth of this sequence?

Crossrefs

Subsequence of A052043.

Cf. A028865, A028868, A028869.

Programs

Mathematica

Select[Prime[Range[100]]^2, IntegerDigits[#] == Sort[IntegerDigits[#]] &] (* Alonso del Arte, Jan 18 2017 *)

PARI

is(n)=my(d=digits(n));d==vecsort(d) && issquare(n,&n) && isprime(n) \\ Charles R Greathouse IV, Jun 05 2013

Extensions

Title changed to reflect terms by Sean A. Irvine, Feb 12 2020