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

1,2

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.

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 *)

Crossrefs

Cf. A004086, A005117.

Sequence in context: A326537 A302798 A294472 * A093501 A087007 A047586

Adjacent sequences: A077334 A077335 A077336 * A077338 A077339 A077340

Keyword

base,easy,nonn,less

Author

Amarnath Murthy, Nov 04 2002

Extensions

More terms from David Wasserman, Oct 25 2006

Status

approved