A002938 The minimal sequence from solving n^3 - m^2 = a(n).

0, 1, 2, 0, 4, 9, 18, 17, 0, 24, 35, 36, 12, 40, 11, 0, 13, 56, 30, 79, 45, 39, 67, 100, 0, 113, 83, 48, 53, 104, 138, 7, 163, 100, 26, 0, 28, 116, 217, 9, 248, 104, 17, 80, 79, 8, 139, 297, 0, 316, 155, 17, 119, 145, 89, 55, 293, 252, 170, 225, 405, 184, 47, 0, 49

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

References

• Marshall Hall, Jr., The Diophantine equation x^3-y^2=k, pp. 173-198 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A077119.

Programs

Mathematica

f1[n_] := n - Floor[Sqrt[n]]^2;
f2[n_] := Ceiling[Sqrt[n]]^2-n;
Table[Min[f1[n^3], f2[n^3]], {n,100}] (* Vladimir Joseph Stephan Orlovsky, Apr 08 2010 *)

PARI

a(n)=vecmin(vector(ceil(n^(3/2)),i,abs(n^3-i^2)))

Formula

a(n) = |A077119(n+1)|.

a(n^2) = 0. - Benoit Cloitre, Aug 17 2002

Extensions

More terms from Benoit Cloitre, Aug 17 2002