

A057905


Positive integers that are not the sum of exactly four positive cubes.


2



1, 2, 3, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 31, 33, 34, 35, 36, 38, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 64, 65, 66, 68, 69, 71, 72, 73, 75, 76, 77, 78, 79, 80, 83, 84, 85, 86, 87
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OFFSET

1,2


COMMENTS

It is conjectured that this sequence is finite, with 7373170279850 as its last member.  Charles R Greathouse IV, Jan 14 2017


LINKS



MATHEMATICA

pr[n_] := Select[ PowersRepresentations[n, 4, 3], FreeQ[#, 0] &]; Select[ Range[90], pr[#] == {} &] (* JeanFrançois Alcover, Nov 08 2012 *)


PROG

(PARI) list(lim)=my(v=List(), e=1+lim\1, x='x, t); t=sum(i=1, sqrtnint(e4, 3), x^i^3, O(x^e))^4; for(n=1, lim, if(polcoeff(t, n)==0, listput(v, n))); Vec(v) \\ Charles R Greathouse IV, Jan 14 2017


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



