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 A139302 #8 Jul 10 2025 16:00:25 %S A139302 2,512,144115188075855872, %T A139302 904625697166532776746648320380374280103671755200316906558262375061821325312 %N A139302 a(n) = 2^(2p - 1)/16, where p is the n-th Mersenne prime A000668(n). %F A139302 a(n) = 2^(2*A000668(n)-1)/16 = A139294(n)/16. %t A139302 a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 7); Array[a, 4] (* _Amiram Eldar_, Jul 10 2025 *) %Y A139302 Cf. A000668, A139294, A139295, A139296, A139297, A139298, A139299, A139300, A139301, A139303, A139304, A139305, A139306. %K A139302 nonn %O A139302 1,1 %A A139302 _Omar E. Pol_, Apr 13 2008 %E A139302 a(4) from _Amiram Eldar_, Jul 10 2025