login
Numbers that are the sum of 4 positive cubes in 1 or more way.
57

%I #38 Dec 26 2021 20:43:42

%S 4,11,18,25,30,32,37,44,51,56,63,67,70,74,81,82,88,89,93,100,107,108,

%T 119,126,128,130,135,137,142,144,145,149,154,156,161,163,168,180,182,

%U 187,191,193,198,200,205,206,217,219,224,226,233,240,243,245,252,254

%N Numbers that are the sum of 4 positive cubes in 1 or more way.

%C It is conjectured that every number greater than 7373170279850 is in this sequence. [See the paper of the same name. - _T. D. Noe_, May 25 2017] - _Charles R Greathouse IV_, Jan 14 2017

%C As the order of addition doesn't matter we can assume terms are in increasing order. - _David A. Corneth_, Aug 01 2020

%H David A. Corneth, <a href="/A003327/b003327.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from T. D. Noe)

%H Jean-Marc Deshouillers, François Hennecart, Bernard Landreau, <a href="https://doi.org/10.1090/S0025-5718-99-01116-3">7373170279850</a>, Math. Comp. 69 (2000), pp. 421-439. Appendix by I. Gusti Putu Purnaba.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CubicNumber.html">Cubic Number.</a>

%e From _David A. Corneth_, Aug 01 2020: (Start)

%e 3888 is in the sequence as 3888 = 6^3 + 6^3 + 12^3 + 12^3.

%e 7729 is in the sequence as 7729 = 2^3 + 4^3 + 14^3 + 17^3.

%e 7875 is in the sequence as 7875 = 5^3 + 10^3 + 15^3 + 15^3. (End)

%o (PARI) list(lim)=my(v=List(),e=1+lim\1,x='x,t); t=sum(i=1,sqrtnint(e-4,3), x^i^3, O(x^e))^4; for(n=4,lim, if(polcoeff(t,n)>0, listput(v,n))); Vec(v) \\ _Charles R Greathouse IV_, Jan 14 2017

%Y Cf. A025403, A057905 (complement), A025411 (distinct).

%Y A###### (x, y): Numbers that are the form of x nonzero y-th powers.

%Y Cf. A000404 (2, 2), A000408 (3, 2), A000414 (4, 2), A003072 (3, 3), A003325 (3, 2), A003327 (4, 3), A003328 (5, 3), A003329 (6, 3), A003330 (7, 3), A003331 (8, 3), A003332 (9, 3), A003333 (10, 3), A003334 (11, 3), A003335 (12, 3), A003336 (2, 4), A003337 (3, 4), A003338 (4, 4), A003339 (5, 4), A003340 (6, 4), A003341 (7, 4), A003342 (8, 4), A003343 (9, 4), A003344 (10, 4), A003345 (11, 4), A003346 (12, 4), A003347 (2, 5), A003348 (3, 5), A003349 (4, 5), A003350 (5, 5), A003351 (6, 5), A003352 (7, 5), A003353 (8, 5), A003354 (9, 5), A003355 (10, 5), A003356 (11, 5), A003357 (12, 5), A003358 (2, 6), A003359 (3, 6), A003360 (4, 6), A003361 (5, 6), A003362 (6, 6), A003363 (7, 6), A003364 (8, 6), A003365 (9, 6), A003366 (10, 6), A003367 (11, 6), A003368 (12, 6), A003369 (2, 7), A003370 (3, 7), A003371 (4, 7), A003372 (5, 7), A003373 (6, 7), A003374 (7, 7), A003375 (8, 7), A003376 (9, 7), A003377 (10, 7), A003378 (11, 7), A003379 (12, 7), A003380 (2, 8), A003381 (3, 8), A003382 (4, 8), A003383 (5, 8), A003384 (6, 8), A003385 (7, 8), A003387 (9, 8), A003388 (10, 8), A003389 (11, 8), A003390 (12, 8), A003391 (2, 9), A003392 (3, 9), A003393 (4, 9), A003394 (5, 9), A003395 (6, 9), A003396 (7, 9), A003397 (8, 9), A003398 (9, 9), A003399 (10, 9), A004800 (11, 9), A004801 (12, 9), A004802 (2, 10), A004803 (3, 10), A004804 (4, 10), A004805 (5, 10), A004806 (6, 10), A004807 (7, 10), A004808 (8, 10), A004809 (9, 10), A004810 (10, 10), A004811 (11, 10), A004812 (12, 10), A004813 (2, 11), A004814 (3, 11), A004815 (4, 11), A004816 (5, 11), A004817 (6, 11), A004818 (7, 11), A004819 (8, 11), A004820 (9, 11), A004821 (10, 11), A004822 (11, 11), A004823 (12, 11), A047700 (5, 2).

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_

%E More terms from _Eric W. Weisstein_