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 A074831 #21 Sep 29 2023 12:00:39 %S A074831 3,20,101,508,3053,20053,141772,1045600,8038954,63830588,518935134, %T A074831 4311185894 %N A074831 Number of binary reversal primes less than 10^n. %C A074831 MathPages counts 1 as being a binary reversal prime whereas the title would exclude it, therefore their count exceeds this count by one. %H A074831 Kevin S. Brown's Mathpages, <a href="http://www.mathpages.com/home/kmath362.htm">Reflective and Cyclic Sets of Primes</a> %H A074831 Cécile Dartyge, Bruno Martin, Joël Rivat, Igor E. Shparlinski, and Cathy Swaenepoel, <a href="https://arxiv.org/abs/2309.11380">Reversible primes</a>, arXiv:2309.11380 [math.NT], 2023. See p. 34. %t A074831 f[n_] := FromDigits[Reverse[IntegerDigits[n, 2]], 2]; NextPrim[n_] := Block[{k = n + 1}, While[ ! PrimeQ[k], k++ ]; k]; c = 0; k = 1; Do[ While[k = NextPrim[k]; k < 10^n, If[ PrimeQ[ f[k]], c++ ]]; k--; Print[c], {n, 16}] %o A074831 (Python) %o A074831 from sympy import isprime, primerange %o A074831 def is_bin_rev_prime(n): return isprime(int(bin(n)[2:][::-1], 2)) %o A074831 def a(n): return sum(is_bin_rev_prime(p) for p in primerange(1, 10**n)) %o A074831 print([a(n) for n in range(1, 7)]) # _Michael S. Branicky_, Mar 20 2021 %K A074831 nonn,base,hard,more %O A074831 1,1 %A A074831 _Robert G. Wilson v_, Sep 09 2002 %E A074831 a(10)-a(11) from _Chai Wah Wu_, Oct 09 2018 %E A074831 a(12) from _Chai Wah Wu_, Oct 10 2018