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 A216765 #21 Oct 15 2020 04:44:50 %S A216765 5,9,10,17,26,28,33,37,50,65,82,101,122,126,129,145,170,197,217,226, %T A216765 244,257,290,325,344,362,401,442,485,513,530,577,626,677,730,785,842, %U A216765 901,962,1001,1025,1090,1157,1226,1297,1332,1370,1445,1522,1601,1682,1729,1765 %N A216765 Perfect powers (squares, cubes, etc.) plus 1. %C A216765 Integers of the form m^k + 1 for integers m, k >= 2. %D A216765 Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.6, p. 113. %H A216765 Vsevolod F. Lev, <a href="https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;fae68ff5.0205">Re: The sequence of 'perfect' powers</a>, Number Theory List, May 21, 2002. %F A216765 a(n) = A001597(n+1) + 1 = A045542(n) + 2. [corrected by _Georg Fischer_, Jun 21 2020] %F A216765 Sum_{n>=1} 1/a(n) = Pi^2/3 - 5/2 (Lev, 2002). - _Amiram Eldar_, Oct 15 2020 %e A216765 a(1) = 2^2 + 1; a(2) = 2^3 + 1; a(3) = 3^2 + 1; a(4) = 2^4 + 1. %Y A216765 Cf. A001597, A045542, A175064, A195055, A214390, A214391. %K A216765 nonn,easy %O A216765 1,1 %A A216765 _Jonathan Vos Post_, Sep 15 2012