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 A051440 #17 Jul 11 2025 08:50:50 %S A051440 3,4,8,20,54,132,312,720,1620,3672,8162,17864,38874,84018,180504, %T A051440 386094,821642,1742538,3681132,7754078,16290048,34136030,71378570, %U A051440 148948140,310248242,645155198,1339484198,2777105130,5750079048,11891268402,24563311310,50685770168,104484802058 %N A051440 a(n) = prime(2^n) + 1. %H A051440 Amiram Eldar, <a href="/A051440/b051440.txt">Table of n, a(n) for n = 0..78</a> %F A051440 a(n) = A033844(n) + 1. %F A051440 a(n) = A018249(n) + 2. - _Amiram Eldar_, Jul 11 2025 %t A051440 a[n_] := Prime[2^n] + 1; Array[a, 33, 0] (* _Amiram Eldar_, Jul 11 2025 *) %o A051440 (PARI) a(n) = prime(2^n) + 1; \\ _Amiram Eldar_, Jul 11 2025 %Y A051440 Cf. A000040, A018249, A033844, A051438, A051439. %K A051440 nonn %O A051440 0,1 %A A051440 _N. J. A. Sloane_ %E A051440 More terms from _Amiram Eldar_, Jul 11 2025