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.
%I A003331 #33 Jun 13 2025 10:58:32 %S A003331 8,15,22,29,34,36,41,43,48,50,55,57,60,62,64,67,69,71,74,76,78,81,83, %T A003331 85,86,88,92,93,95,97,99,100,102,104,106,107,111,112,113,114,118,119, %U A003331 120,121,123,125,126,130,132,133,134,137,138,139,140,141,144,145,146,148,149 %N A003331 Numbers that are the sum of 8 positive cubes. %C A003331 620 is the largest among only 142 positive integers not in this sequence. This can be proved by induction. - _M. F. Hasler_, Aug 13 2020 %H A003331 David A. Corneth, <a href="/A003331/b003331.txt">Table of n, a(n) for n = 1..10000</a> %H A003331 OEIS Wiki, <a href="/wiki/Index_to_Sums_of_like_powers">Index to sequences related to sums of like powers</a>. %H A003331 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A003331 a(n) = 142 + n for all n > 478. - _M. F. Hasler_, Aug 13 2020 %e A003331 From _David A. Corneth_, Aug 01 2020: (Start) %e A003331 1796 is in the sequence as 1796 = 4^3 + 4^3 + 4^3 + 4^3 + 5^3 + 7^3 + 7^3 + 9^3. %e A003331 2246 is in the sequence as 2246 = 2^3 + 4^3 + 5^3 + 5^3 + 5^3 + 5^3 + 7^3 + 11^3. %e A003331 3164 is in the sequence as 3164 = 5^3 + 5^3 + 6^3 + 6^3 + 8^3 + 8^3 + 9^3 + 9^3.(End) %t A003331 Module[{upto=200,c},c=Floor[Surd[upto,3]];Select[Union[Total/@ Tuples[ Range[ c]^3,8]],#<=upto&]] (* _Harvey P. Dale_, Jan 11 2016 *) %o A003331 (PARI) (A003331_upto(N, k=8, m=3)=[i|i<-[1..#N=sum(n=1, sqrtnint(N, m), 'x^n^m, O('x^N))^k], polcoef(N, i)])(150) \\ _M. F. Hasler_, Aug 02 2020 %o A003331 A003331(n)=if(n>478, n+142, n>329, n+141, A003331_upto(470)[n]) \\ _M. F. Hasler_, Aug 13 2020 %o A003331 (Python) %o A003331 from itertools import combinations_with_replacement as mc %o A003331 def aupto(lim): %o A003331 cbs = (i**3 for i in range(1, int((lim-7)**(1/3))+2)) %o A003331 return sorted(set(k for k in (sum(c) for c in mc(cbs, 8)) if k <= lim)) %o A003331 print(aupto(150)) # _Michael S. Branicky_, Aug 15 2021 %Y A003331 Other sequences of numbers that are the sum of x nonzero y-th powers: %Y A003331 A000404 (x=2, y=2), A000408 (3, 2), A000414 (4, 2), A047700 (5, 2), %Y A003331 A003325 (2, 3), A003072 (3, 3), A003327 .. A003335 (4 .. 12, 3), %Y A003331 A003336 .. A003346 (2 .. 12, 4), A003347 .. A003357 (2 .. 12, 5), %Y A003331 A003358 .. A003368 (2 .. 12, 6), A003369 .. A003379 (2 .. 12, 7), %Y A003331 A003380 .. A003390 (2 .. 12, 8), A003391 .. A004801 (2 .. 12, 9), %Y A003331 A004802 .. A004812 (2 .. 12, 10), A004813 .. A004823 (2 .. 12, 11). %K A003331 nonn,easy %O A003331 1,1 %A A003331 _N. J. A. Sloane_