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 A102384 #11 Oct 02 2024 09:18:48 %S A102384 1,2,2,2,61,23,2,821,2,5,4201,2,2,2,137,7,2,270131,2,5,13,2,2,2, %T A102384 61277761,17,2,7,2,5,3373,2,2,2,113647,53,2,274359834731,2,5,109,2,2, %U A102384 2,19,23888027348153,7,34613,2,5,7,2,2,1091,919,86936981079782063,139,29 %N A102384 a(n) = A020639(A004094(n)). %e A102384 n = 25 -> 2^25 = 33554432 -> 23445533 = 17*23*61*983: a(25) = 17. %t A102384 a[n_] := FactorInteger[IntegerReverse[2^n]][[1, 1]]; Array[a, 60, 0] (* _Amiram Eldar_, Oct 02 2024 *) %o A102384 (PARI) a(n) = if(n == 0, 1, factor(fromdigits(Vecrev(digits(2^n))))[1,1]); \\ _Amiram Eldar_, Oct 02 2024 %Y A102384 Cf. A004094, A020639, A102382, A102383, A102385. %K A102384 nonn,base %O A102384 0,2 %A A102384 _Reinhard Zumkeller_, Jan 06 2005 %E A102384 Corrected by _T. D. Noe_, Nov 15 2006