cp's OEIS Frontend

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.

A319034 Decimal expansion of the height that minimizes the total surface area of the four triangular faces of a square pyramid of unit volume.

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%I A319034 #22 Feb 16 2025 08:33:56
%S A319034 1,1,4,4,7,1,4,2,4,2,5,5,3,3,3,1,8,6,7,8,0,8,0,4,2,2,1,1,9,3,9,6,7,7,
%T A319034 0,0,8,9,1,5,9,0,6,9,2,0,7,8,7,9,3,1,0,7,2,0,9,9,0,5,2,1,7,4,0,6,5,6,
%U A319034 7,4,2,9,9,0,2,4,2,1,4,1,5,0,4,3,7,6,0,8,1,6,1,0,3,0,9,1,7,0,4,5
%N A319034 Decimal expansion of the height that minimizes the total surface area of the four triangular faces of a square pyramid of unit volume.
%C A319034 A square pyramid with a height of h and a base of size s X s has volume V = (1/3)*s^2*h, so a square pyramid of unit volume has s = sqrt(3/h), and the slant height of each of the four triangular faces is t = sqrt(h^2 + (s/2)^2) = sqrt(h^2 + 3/(4*h)), and the total area of the four faces is A = 4*(s*t/2) = sqrt(12*h^3 + 9)/h; this area is minimized at h = (3/2)^(1/3), where it reaches A = 3^(7/6)*2^(1/3).
%C A319034 If the total surface area of all five faces including the square base is to be minimized, then the resulting height is 6^(1/3) (cf. A005486). - _Jon E. Schoenfield_, Nov 11 2018
%H A319034 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Pyramid.html">Pyramid</a>.
%F A319034 Equals (3/2)^(1/3) = (1/2)*A010584.
%F A319034 Equals A002581/A002580. - _Michel Marcus_, Oct 23 2018
%e A319034 1.14471424255333186780804221193967700891590692078793...
%t A319034 RealDigits[Surd[3/2, 3], 10, 120][[1]] (* _Amiram Eldar_, Jun 21 2023 *)
%o A319034 (PARI) sqrtn(3/2, 3) \\ _Michel Marcus_, Oct 23 2018
%Y A319034 Cf. A002580, A002581, A005486, A010584.
%K A319034 nonn,cons
%O A319034 1,3
%A A319034 _Jon E. Schoenfield_, Oct 22 2018