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 A048851 #23 May 25 2023 12:49:55 %S A048851 8,13,34,74,170,290,458,650,890,1370,1802,2330,3050,3530,4058,5018, %T A048851 6290,7202,8210,9530,10370,11570,13130,14810,17330,19610,20810,22058, %U A048851 23330,24650,28898,33290,35930,38090,41522,45002,47450,51218,54458 %N A048851 Length of hypotenuse squared in right triangle formed by a prime spiral plotted in Cartesian coordinates. %D A048851 H. E. Huntley, The Divine Proportion, A Study in Mathematical Beauty. New York: Dover, 1970. See Chapter 13, Spira Mirabilis, especially Fig. 13-5, page 173. %F A048851 To begin prime spiral, plot (2, 0), (0, 2). Square of hypotenuse is c^2 = a^2 + b^2, or 8 = 4 + 4, so a(1) = 8. %F A048851 a(n) = A069484(n-1), n >= 2. - _Mamuka Jibladze_, Mar 24 2017 %e A048851 a(2) = 13 because c^2 = a^2 + b^2 = 4 + 9 = 13. %Y A048851 Cf. A006094. %K A048851 easy,nonn %O A048851 1,1 %A A048851 _Enoch Haga_