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.
%I A065726 #21 Dec 05 2024 19:12:15 %S A065726 2,3,5,7,11,19,31,43,59,67,71,89,137,151,179,191,199,223,251,257,281, %T A065726 283,307,311,337,353,359,367,383,409,419,433,443,449,523,563,617,619, %U A065726 641,659,727,787,809,811,857,887,907,919,947,977,1033,1039,1097,1123 %N A065726 Primes p whose base-8 expansion is also the decimal expansion of a prime. %C A065726 In general rebase notation (Marc LeBrun): p8 = (8) [p] (10). %H A065726 Harry J. Smith, <a href="/A065726/b065726.txt">Table of n, a(n) for n = 1..1000</a> %H A065726 M. F. Hasler, <a href="https://docs.google.com/document/d/10IM7fcAbB2tqRGuwfGvuEGUzD_IXbgXPDK0tfxN4M3o/pub">Primes whose base c expansion is also the base b expansion of a prime</a> %e A065726 E.g., 787_10 = 1423_8 is prime, and so is 1423_10. %t A065726 Select[ Range[2500], PrimeQ[ # ] && PrimeQ[ FromDigits[ IntegerDigits[ #, 8]]] & ] %o A065726 (PARI) is(p, b=10, c=8)=isprime(vector(#d=digits(p, c), i, b^(#d-i))*d~)&&isprime(p) \\ This code can be used for other bases b, c when b>c. See A235265 for code also valid for b<c. \\ _M. F. Hasler_, Jan 12 2014 %Y A065726 Primes in A036963. %Y A065726 Cf. A065720 up to A065727, A065361. %Y A065726 Cf. A090707 - A091924, A235461 - A235482. See the LINK for further cross-references. %K A065726 nonn,base %O A065726 1,1 %A A065726 _Patrick De Geest_, Nov 15 2001 %E A065726 Definition clarified by _M. F. Hasler_, Jan 12 2014