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 A235638 #15 Nov 02 2023 11:07:23 %S A235638 2,3,5,13,17,29,37,41,73,97,109,137,149,173,193,197,229,233,281,293, %T A235638 337,521,541,557,601,613,617,673,677,733,797,877,1033,1061,1069,1117, %U A235638 1129,1217,1237,1301,1321,1381,1549,1553,1609,1621,1693,1733,1889,1901,2069,2137,2221,2273,2309 %N A235638 Primes whose base-8 representation also is the base-6 representation of a prime. %C A235638 This sequence is part of the two-dimensional array of sequences based on this same idea for any two different bases b, c > 1. Sequence A235265 and A235266 are the most elementary ones in this list. Sequences A089971, A089981 and A090707 through A090721, and sequences A065720 - A065727, follow the same idea with one base equal to 10. %H A235638 Robert Price, <a href="/A235638/b235638.txt">Table of n, a(n) for n = 1..11493</a> %H A235638 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 A235638 E.g., 13 = 15_8 and 15_6 = 11 are both prime. %o A235638 (PARI) is(p,b=6,c=8)=vecmax(d=digits(p,c))<b&&isprime(vector(#d,i,b^(#d-i))*d~)&&isprime(p) %o A235638 (PARI) forprime(p=1,3e3,is(p,8,6)&&print1(vector(#d=digits(p,6),i,8^(#d-i))*d~,",")) \\ To produce the terms, this is more efficient than to select them using straightforwardly is(.)=is(.,6,8) %Y A235638 Cf. A235631, A235265, A235266, A152079, A235461 - A235482, A065720 - A065727, A235394, A235395, A089971 ⊂ A020449, A089981, A090707 - A091924, A235615 - A235639. See the LINK for further cross-references. %K A235638 nonn,base %O A235638 1,1 %A A235638 _M. F. Hasler_, Jan 13 2014