cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A141263 Lesser of a prime/emirp pair.

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%I A141263 #26 Sep 27 2024 23:21:22
%S A141263 2,3,5,7,11,13,17,37,79,101,107,113,131,149,151,157,167,179,181,191,
%T A141263 199,313,337,347,353,359,373,383,389,709,727,739,757,769,787,797,919,
%U A141263 929,1009,1021,1031,1033,1061,1069,1091,1097,1103,1109,1151,1153,1181
%N A141263 Lesser of a prime/emirp pair.
%C A141263 From the set of numbers that are both prime and emirp choose the smaller one of each pair (whenever more than one decimal digit is involved).
%C A141263 A002385 is subset of this sequence.
%H A141263 Chai Wah Wu, <a href="/A141263/b141263.txt">Table of n, a(n) for n = 1..1000</a>
%e A141263 31 does not appear since we have already seen 13.
%t A141263 pp[n_] := Module[{nr=FromDigits[Reverse[IntegerDigits[n]]]}, If[PrimeQ[nr],Sort[{n,nr}]]]; Transpose[Rest[Union[pp/@Prime[Range[200]]]]][[1]] (* _Harvey P. Dale_, Dec 18 2010 *)
%o A141263 (Python)
%o A141263 from gmpy2 import next_prime, is_prime
%o A141263 A141263_list, p = [], 1
%o A141263 for _ in range(1, 10**4):
%o A141263     p = next_prime(p)
%o A141263     ps = int(str(p)[::-1])
%o A141263     if p <= ps and is_prime(ps):
%o A141263         A141263_list.append(int(p)) # _Chai Wah Wu_, Jun 11 2015
%Y A141263 Cf. A002385, A007500.
%K A141263 nonn,base
%O A141263 1,1
%A A141263 _Artur Jasinski_, Jun 20 2008