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A038597
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Numbers n such that n^2 is a difference between 2 positive cubes in at least one way.
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10
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13, 28, 49, 104, 147, 181, 189, 224, 351, 361, 388, 392, 507, 549, 588, 676, 756, 832, 1029, 1176, 1323, 1369, 1425, 1448, 1512, 1625, 1792, 1862, 1911, 1922, 2299, 2355, 2521, 2808, 2883, 2888, 3104, 3136, 3185, 3216, 3500, 3721, 3969, 4056, 4103, 4332
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OFFSET
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1,1
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LINKS
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Donovan Johnson, Table of n, a(n) for n = 1..1000
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FORMULA
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a(n) = sqrt(A038596(n)). - M. F. Hasler, Oct 05 2013
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PROG
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(PARI) is(n)=my(N=n^2); for(k=sqrtnint(N, 3)+1, (sqrtint(12*N-3)+3)\6, if(ispower(N-k^3, 3), return(1))); 0 \\ Charles R Greathouse IV, Oct 28 2013
(PARI) mm=820188; cb=vector(mm); for(i=1, mm, cb[i]=i^3); mb=1420608; v=vector(mb); mx=mb^2; for(i=1, mm-1, for(j=i+1, mm, d=cb[j]-cb[i]; if(d<=mx, if(issquare(d, &r), v[r]=1), next(2)))); c=0; for(n=1, mb, if(v[n]==1, c++; write("b038597.txt", c " " n))) \\ Donovan Johnson, Oct 31 2013
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CROSSREFS
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Cf. A038593-A038598.
Sequence in context: A063309 A098847 A161453 * A026054 A001291 A018974
Adjacent sequences: A038594 A038595 A038596 * A038598 A038599 A038600
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KEYWORD
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nonn
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AUTHOR
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Jeff Burch
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EXTENSIONS
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More terms from Jud McCranie
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STATUS
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approved
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