A263241 Lesser of emirp pairs that are merely reversals of their end digits.

13, 17, 37, 79, 107, 113, 149, 157, 167, 179, 199, 337, 347, 359, 389, 709, 739, 769, 1009, 1223, 1229, 1559, 1669, 3889, 7229, 10007, 10009, 10909, 11717, 11719, 12227, 12323, 12829, 13337, 13933, 14143, 14447, 14449, 14549, 14843, 14947, 15053, 16063, 16267, 16567, 16763

Offset

1,1

Comments

The first digit is always smaller than last digit.

Links

Table of n, a(n) for n=1..46.

Mathematica

Select[Range[20000], And @@ PrimeQ[{#, IntegerReverse[#]}] && ! PalindromeQ[#] && First[(d = IntegerDigits[#])] < Last[d] && PalindromeQ[Most@ Rest@ IntegerDigits[#]] &] (* Amiram Eldar, Oct 16 2021 *)

Prog

(PARI) isok(p) = my(dp=digits(p), dr=Vecrev(dp), r=fromdigits(dr)); if (isprime(r) && (r>p) && isprime(p), sum(i=2, #dp-1, dp[i]==dr[i]) == #dp-2); \\ Michel Marcus, Oct 16 2021

Crossrefs

Cf. A006567, A109308, A263240, A263242.

Sequence in context: A322472 A166681 A109308 * A246944 A086402 A358571

Adjacent sequences: A263238 A263239 A263240 * A263242 A263243 A263244

Keyword

nonn,base

Author

Lekraj Beedassy, Oct 13 2015

Extensions

Missing 179 added by Zak Seidov, Oct 15 2021

Status

approved