A059799 Primes which when added to their reversals are squares.

2, 29, 47, 83, 263, 461, 20147, 23117, 24107, 63113, 80141, 81131, 300893, 301793, 303593, 308093, 310883, 313583, 324473, 333563, 336263, 342653, 344453, 348053, 350843, 354443, 355343, 356243, 362633, 363533, 364433, 365333, 377123, 378023

Offset

1,1

Comments

Idea from Carlos Rivera's The Prime Puzzles and Problems Connection, Conjecture 23.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..683 (* all such primes up to the 20 millionth prime *)

Formula

Add prime to its reverse. If a square, add to sequence.

Example

a(4)=263 because 263+362=625 and 625 is a square whose root is 25.

Mathematica

Select[Prime[Range[33000]], IntegerQ[Sqrt[FromDigits[Reverse[ IntegerDigits[#]]]+ #]]&] (* Harvey P. Dale, Aug 18 2012 *)

Crossrefs

Cf. A035519, A059798.

Cf. A227371 (indices of primes).

Sequence in context: A330895 A105893 A366692 * A367796 A142969 A281546

Adjacent sequences: A059796 A059797 A059798 * A059800 A059801 A059802

Keyword

easy,nonn,base

Author

Enoch Haga, Feb 23 2001

Status

approved