A125110 Cubes which have a partition as the sum of 2 squares.
0, 1, 8, 64, 125, 512, 729, 1000, 2197, 4096, 4913, 5832, 8000, 15625, 17576, 24389, 32768, 39304, 46656, 50653, 64000, 68921, 91125, 117649, 125000, 140608, 148877, 195112, 226981, 262144, 274625, 314432, 373248, 389017, 405224, 512000, 531441
Offset: 1
Keywords
Examples
125 = 5^3 = 2^2 + 11^2 = A001481(54) = A000578(8).
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[Range[0, 81]^3, SquaresR[2, # ] > 0 &] (* Ray Chandler, Nov 23 2006 *)
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PARI
isA125110(ncube)={ local(a) ; a=0; while(a^2<=ncube, if(issquare(ncube-a^2), return(1) ; ) ; a++ ; ) ; return(0) ; } { for(n=0,200, if(isA125110(n^3), print1(n^3,",") ; ) ; ) ; } \\ R. J. Mathar, Nov 23 2006
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Python
from itertools import count, islice from sympy import factorint def A125110_gen(): # generator of terms return map(lambda m:m**3,filter(lambda n:all(p & 3 != 3 or e & 1 == 0 for p, e in factorint(n).items()),count(0))) A125110_list = list(islice(A125110_gen(),20)) # Chai Wah Wu, Jun 27 2022
Formula
a(n) = A001481(n)^3. - Ray Chandler, Nov 23 2006
Extensions
Corrected and extended by R. J. Mathar and Ray Chandler, Nov 23 2006