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 A038593 Differences between positive cubes in 1, 2 or 3 ways: union of A014439, A014440 and A014441. 43
 7, 19, 26, 37, 56, 61, 63, 91, 98, 117, 124, 127, 152, 169, 189, 208, 215, 217, 218, 271, 279, 296, 316, 331, 335, 342, 386, 387, 397, 448, 469, 485, 488, 504, 511, 513, 547, 602, 604, 631, 657, 665, 702, 721, 728, 784, 817, 819, 866, 875, 919, 936, 973, 988 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 MAPLE N:= 1000: # to get all terms <= N X:= floor(sqrt(N/3)): V:= Vector(N): for x from 2 to X do   if x^3 > N then      y0:= iroot(x^3-N, 3);      if x^3 - y0^3 > N then y0:= y0+1 fi;   else y0:= 1 fi;   for y from y0 to x-1 do      V[x^3 - y^3] := V[x^3 - y^3]+1   od od: select(t -> V[t] <= 3 and V[t]>=1, [\$1..N]); # Robert Israel, Dec 10 2015 MATHEMATICA r = 988; p = 3; Sort@Drop[Flatten@Select[Tally@Reap[Do[n = i^p - j^p; If[n <= r, Sow[n]], {i, Ceiling[(r/p)^(1/(p - 1))]}, {j, i}]][[2, 1]], 0 < #[[2]] < 4 &], {2, -1, 2}] (* Arkadiusz Wesolowski, Dec 10 2015 *) CROSSREFS Cf. A038594, A038595, A038596, A038597, A038598. Sequence in context: A003282 A006063 A181123 * A014439 A175376 A175366 Adjacent sequences:  A038590 A038591 A038592 * A038594 A038595 A038596 KEYWORD nonn AUTHOR EXTENSIONS Corrected by Don Reble (djr(AT)nk.ca), Nov 19 2006 STATUS approved

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