login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 


Squares that are both a sum and a difference of two positive cubes.
2

%I #33 Apr 22 2016 04:58:45

%S 345744,1058841,1750329,8340544,22127616,67765824,68574961,95004009,

%T 112021056,252047376,533794816,771895089,1097199376,1232922769,

%U 1275989841,1416167424,2217373921,4337012736,4388797504,5402250000,5554571841,6080256576,7169347584,10721359936

%N Squares that are both a sum and a difference of two positive cubes.

%C Intersection of A050802 and A038596.

%C Square terms of sequence A225908. - _Michel Marcus_, Apr 22 2016

%D Ian Stewart, "Game, Set and Math", Dover, 2007, Chapter 8 'Close Encounters of the Fermat Kind', pp. 107-124.

%H Donovan Johnson and Chai Wah Wu, <a href="/A230717/b230717.txt">Table of n, a(n) for n = 1..500</a> n = 1..100 from Donovan Johnson

%H <a href="/index/Su#ssq">Index to sequences related to sums of cubes</a>

%F a(n) = k^2 = a^3 + b^3 = c^3 - d^3 for some natural numbers k, a, b, c, d.

%F a(n) = A230716(n)^2.

%e 345744 = 588^2 = 14^3 + 70^3 = 71^3 - 23^3.

%o (PARI) isA038596(n)=for(k=sqrtnint(n,3)+1,(sqrtint(12*n-3)+3)\6,if(ispower(n-k^3,3), return(issquare(n)))); 0

%o isA050802(n)=for(k=sqrtnint((n+1)\2, 3), sqrtnint(n-1, 3), if(ispower(n-k^3, 3), return(issquare(n)))); 0

%o is(n)=isA038596(n) && isA050802(n) \\ _Charles R Greathouse IV_, Oct 28 2013

%Y Cf. A050801, A050802, A038596, A038597, A225908, A230716.

%K nonn

%O 1,1

%A _Jonathan Sondow_, Oct 28 2013

%E a(5)-a(24) from _Donovan Johnson_, Oct 28 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 14:45 EDT 2024. Contains 376087 sequences. (Running on oeis4.)