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 A379938 #14 Jan 07 2025 09:52:04 %S A379938 1,9,18,142,575,23652,3633466,10846595429,802467018101, %T A379938 2289255503212477 %N A379938 Numbers k such that the k-th prime is a power of two reversed. %F A379938 A000040(a(n)) = A102385(n). %F A379938 a(n) = A000720(A102385(n)). - _Michel Marcus_, Jan 07 2025 %e A379938 The 9th prime is 23, 23 reversed is 32, and 32 = 2^5, so 9 is a term. %o A379938 (Python) %o A379938 import sympy %o A379938 for (k, p) in enumerate(sympy.primerange(10**8)): %o A379938 rev = int(str(p)[::-1]) %o A379938 # is rev a power of two (or zero)? %o A379938 if rev & (rev - 1) == 0: %o A379938 print(k + 1, end=",") %o A379938 print() %Y A379938 Cf. A000040, A000079, A004087, A004094, A057708, A102385. %K A379938 base,nonn,more %O A379938 1,2 %A A379938 _Kalle Siukola_, Jan 06 2025 %E A379938 a(8)-a(10) from _Amiram Eldar_, Jan 07 2025