A004438 Numbers that are not the sum of 5 distinct squares.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 47, 48, 49, 52, 53, 56, 58, 59, 60, 61, 64, 67, 68, 69, 72, 73, 76, 77, 80, 83, 89, 92, 96, 97, 101, 104, 108, 112, 124, 128, 136, 188, 224

Offset

1,2

Links

Table of n, a(n) for n=1..76.

Paul T. Bateman, Adolf J. Hildebrand and George B. Purdy, Sums of distinct squares, Acta Arith. 67 (1994), 349-380.

E. M. Wright, The representation of a number as a sum of five or more squares, Quart. J. Math. Oxford Ser. 4 (1933), 37-51.

Index entries for sequences related to sums of squares

Mathematica

nn=10000; t=Table[0, {nn}]; lim=Floor[Sqrt[nn]]; sq=Table[i^2, {i, 0, lim}]; lim=lim+1; Do[n=sq[[i1]]+sq[[i2]]+sq[[i3]]+sq[[i4]]+sq[[i5]]; If[n<=nn, t[[n]]++ ], {i1, lim}, {i2, i1+1, lim}, {i3, i2+1, lim}, {i4, i3+1, lim}, {i5, i4+1, lim}]; Flatten[Position[t, 0]] (* T. D. Noe, Jul 24 2006 *)
j[{a_, b_, c_, d_, e_}] := If[0 <= a < b < c < d < e, a^2 + b^2 + c^2 + d^2 + e^2, False]; Union[ Complement[Range[500], DeleteCases[ Flatten[Map[j, PowersRepresentations[ #, 5, 2]] & /@ Range[500]], False]]] (* Ant King, Sep 30 2010 *)

Crossrefs

Cf. A120951.

Sequence in context: A070915 A083243 A004441 * A109425 A357873 A226537

Adjacent sequences: A004435 A004436 A004437 * A004439 A004440 A004441

Keyword

nonn,fini,full

Author

N. J. A. Sloane

Extensions

More terms from Franklin T. Adams-Watters, Jul 18 2006

Status

approved