The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A274128 Numbers n such that n and n^2 are both a sum of two positive cubes. 1
 39312, 251370, 314496, 432523, 948051, 1061424, 1536416, 2010960, 2515968, 3009825, 3460184, 4914000, 6786990, 6822900, 7154784, 7584408, 7825545, 8491392, 11678121, 12291328, 13484016, 16087680, 20127744, 24078600, 25501762, 25597377 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n such that n^k is the sum of two positive cubes for all k not divisible by 3. The restriction on the values of k is the result of Fermat's Last Theorem. Inspiration was Taxi-cab number 39312. It is the least number with the property that sequence focuses on. LINKS Chai Wah Wu, Table of n, a(n) for n = 1..1646 EXAMPLE 251370 is a term because 251370 = 29^3 + 61^3 and 251370^2 = 2961^3 + 3339^3. PROG (PARI) isA003325(n) = for(k=1, sqrtnint(n\2, 3), ispower(n-k^3, 3) && return(1)); lista(nn) = for(n=1, nn, if(isA003325(n) && isA003325(n^2), print1(n, ", "))); CROSSREFS Cf. A003325. Sequence in context: A250515 A031667 A196200 * A144306 A234033 A253940 Adjacent sequences: A274125 A274126 A274127 * A274129 A274130 A274131 KEYWORD nonn AUTHOR Altug Alkan, Jun 10 2016 STATUS approved

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

Last modified May 21 02:29 EDT 2024. Contains 372720 sequences. (Running on oeis4.)