A263241 -id:A263241 - cp's OEIS frontend

A263242 Larger of emirp pairs that are merely reversals of their end digits.

31, 71, 73, 97, 311, 701, 733, 743, 751, 761, 907, 937, 941, 953, 967, 971, 983, 991, 3221, 9001, 9221, 9227, 9551, 9661, 9883, 32321, 33931, 34141, 34841, 35051, 36061, 36761, 37571, 39791, 70001, 71711, 72221, 73331, 74143, 74441, 74843, 74941, 75253, 76261, 76463, 76561

Offset: 1

Lekraj Beedassy, Oct 13 2015

The first digit is always larger than the last digit.

Harvey P. Dale, Table of n, a(n) for n = 1..500

Cf. A006567, A109309, A263240, A263241.

epQ[n_]:=Module[{idn=IntegerDigits[n],mid},mid=Rest[Most[idn]];PrimeQ[ IntegerReverse[n]]&&mid==Reverse[mid]&&idn[[1]]>idn[[-1]]]; Select[ Prime[Range[6,8000]],epQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 10 2016 *)

Corrected by Harvey P. Dale, Oct 10 2016

A263240 Emirps whose reversals are merely their end digits swapped.

Original entry on oeis.org

13, 17, 31, 37, 71, 73, 79, 97, 107, 113, 149, 157, 167, 179, 199, 311, 337, 347, 359, 389, 701, 709, 733, 739, 743, 751, 761, 769, 907, 937, 941, 953, 967, 971, 983, 991, 1009, 1223, 1229, 1559, 1669, 3221, 3889, 7229, 9001, 9221, 9227, 9551, 9661, 10007, 10009, 10909, 11717, 11719, 12227, 12323, 12829, 13337, 13933, 14143, 14447, 14449, 14549, 14843, 14947

Offset: 1

Lekraj Beedassy, Oct 13 2015

Subsequence of emirps A006567 with which it is identical for the first 37 terms.

Entries with 4 or more digits consist of a middle repdigit or palindrome part inserted between the end digits.

Cf. A006567, A263241, A263242.

cp's OEIS Frontend

A263242 Larger of emirp pairs that are merely reversals of their end digits.

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