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A059799 Primes which when added to their reversals are squares. 5
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 (list; graph; refs; listen; history; text; internal format)
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: A256472 A330895 A105893 * A142969 A281546 A115448

Adjacent sequences:  A059796 A059797 A059798 * A059800 A059801 A059802

KEYWORD

easy,nonn,base

AUTHOR

Enoch Haga, Feb 23 2001

STATUS

approved

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Last modified August 8 02:45 EDT 2020. Contains 336290 sequences. (Running on oeis4.)