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A087285
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Possible differences between a cube and the next smaller square.
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6
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2, 4, 7, 11, 13, 15, 19, 20, 26, 28, 35, 39, 40, 45, 47, 48, 49, 53, 55, 56, 60, 63, 67, 74, 76, 79, 81, 83, 100, 104, 107, 109, 116, 127, 135, 139, 146, 147, 148, 150, 152, 155, 170, 174, 180, 184, 186, 191, 193, 200, 207, 212, 215, 216, 233, 235, 242, 244, 249
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Sequence and program were provided by Ralf Stephan (ralf(AT)ark.in-berlin.de) Aug 28 2003.
Comment from David Wilson (davidwwilson(AT)comcast.net), Jan 05 2009: I believe there is an algorithm for solving x^3 - y^2 = k, which should have a finite number of solutions for any k. That means that we should in principle be able to compute this sequence.
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REFERENCES
| See under A081121.
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EXAMPLE
| a(1)=2 because the next smaller square below 3^3=27 is 5^2=25.
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PROG
| (PARI) v=vector(200):for(n=2, 10^7, t=n^3:s=sqrtint(t)^2: if(s==t, s=sqrtint(t-1)^2):tt=t-s: if(tt>0&&tt<=200&&!v[tt], v[tt]=n)):for(k=1, 200, if(v[k], print1(k", ")))
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CROSSREFS
| Cf. A087286, A088017, A081121, A077116, A065733.
Sequence in context: A140794 A127575 A106265 * A107791 A181518 A191323
Adjacent sequences: A087282 A087283 A087284 * A087286 A087287 A087288
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KEYWORD
| nonn
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AUTHOR
| Hugo Pfoertner (hugo(AT)pfoertner.org), Sep 18 2003
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