A077337 Numbers k such that k and R(k) both are squarefree where R(n) (A004086) is the digit reversal of n.

1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 22, 26, 30, 31, 33, 34, 35, 37, 38, 39, 41, 43, 47, 51, 53, 55, 58, 59, 62, 66, 70, 71, 73, 74, 77, 78, 79, 83, 85, 87, 91, 93, 95, 97, 101, 102, 103, 105, 106, 107, 109, 110, 111, 113, 114, 115, 118, 119, 122, 123, 127, 129

Offset: 1

Author

Amarnath Murthy, Nov 04 2002

Keywords

• base
• easy
• nonn
• less

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Cécile Dartyge, Bruno Martin, Joël Rivat, Igor E. Shparlinski, and Cathy Swaenepoel, Reversible primes, arXiv:2309.11380 [math.NT], 2023. See p. 6.

Crossrefs

Cf. A004086, A005117.

Programs

Mathematica

Select[Range[200],And@@SquareFreeQ/@{#,FromDigits[Reverse[ IntegerDigits[ #]]]}&] (* Harvey P. Dale, Jan 04 2014 *)
Select[Range[200],AllTrue[{#,IntegerReverse[#]},SquareFreeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 16 2018 *)

Extensions

More terms from David Wasserman, Oct 25 2006