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.

A274012 Integers n such that n^3 is the average of a nonzero square and a nonzero fourth power.

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%I A274012 #25 Jul 18 2016 20:46:53
%S A274012 1,5,16,25,26,40,41,50,80,81,125,250,256,365,386,400,405,416,425,450,
%T A274012 457,477,625,626,640,656,800,841,845,1000,1125,1153,1210,1225,1280,
%U A274012 1296,1681,1825,2000,2025,2057,2106,2197,2312,2401,3042,3125,3240,3250,3321,3362,3400,3625
%N A274012 Integers n such that n^3 is the average of a nonzero square and a nonzero fourth power.
%C A274012 Numbers n such that 2*n^3 = x^2 + y^4 where x and y are nonzero integers, is soluble.
%C A274012 Square terms of this sequence are 1, 16, 25, 81, 256, 400, 625, 841, 1225, 1296, 1681, 2025, 2401, ...
%C A274012 From _David A. Corneth_, Jun 06 2016 (Start):
%C A274012 A000351, the powers of 5, is a subsequence.
%C A274012 If n is a term, then n * k^4 is a term; as 2*n^3 = x^4 + y^2, 2 * (n * k^4)^3 = (k^3 * x)^4 + (k^6 * y)^2. (End)
%H A274012 Chai Wah Wu, <a href="/A274012/b274012.txt">Table of n, a(n) for n = 1..10000</a>
%e A274012 5 is a term because 5^3 = (13^2 + 3^4) / 2.
%o A274012 (PARI) is(n) = for(x=1, (2*n) ^ 0.75, if(issquare(2*n^3 - x^4)&&2*n^3-x^4>0, return(1)); 0) \\ _David A. Corneth_, Jun 06 2016
%Y A274012 Cf. A266212.
%K A274012 nonn
%O A274012 1,2
%A A274012 _Altug Alkan_, Jun 06 2016