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 A261071 #25 Jan 31 2024 03:58:30 %S A261071 3,5,65,16777217,1329227995784915872903807060280344577 %N A261071 a(n) = 2^(n!) + 1. %C A261071 a(n) is a sum of two k-th powers of positive integers for k=1,2,...,n. %F A261071 a(n) = 2^(n!) + 1. %F A261071 a(n) = A050923(n) + 1. %e A261071 a(3) = 2^6 + 1 = 65. %t A261071 Array[2^#! + 1 &, 6] (* _Paolo Xausa_, Jan 31 2024 *) %o A261071 (PARI) first(m)=vector(m,i,2^(i!)+1); /* _Anders Hellström_, Aug 08 2015 */ %o A261071 (Magma) [2^(Factorial(n)) + 1: n in [1..6]]; // _Vincenzo Librandi_, Aug 09 2015 %Y A261071 Cf. A050923. %K A261071 nonn,easy %O A261071 1,1 %A A261071 _Marco Ripà_, Aug 08 2015