cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A129210 Largest number not the sum of n distinct nonzero squares.

Original entry on oeis.org

245, 333, 330, 462, 539, 647, 888, 1036, 1177, 1445, 1722, 1990, 2311, 2672, 3047, 3492, 4093, 4613, 5138, 5718, 6379, 7123, 7952, 8676, 9537, 10393, 11558, 12602, 13743, 14863, 16252, 17528, 18957, 20481, 22042, 23678, 25347, 27207, 29092
Offset: 5

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Author

T. D. Noe, Apr 03 2007

Keywords

Comments

Halter-Koch essentially finds (5)-a(12) (with a coprimality condition, but Bateman, Hildebrand, & Purdy show that this can be dropped). - Charles R Greathouse IV, Mar 18 2014

Crossrefs

Cf. A120951 (numbers that are not the sum of 5 distinct nonzero squares).

Formula

Bateman, Hildebrand, & Purdy prove that a(n) = n^3/3 + n^2/2 + sqrt(8)*n^(3/2) + O(n^(5/4)), see their Theorem 1. - Charles R Greathouse IV, Mar 31 2025

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

Original entry on oeis.org

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

Views

Author

Keywords

Crossrefs

Cf. A120951.

Programs

  • 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 *)

Extensions

More terms from Franklin T. Adams-Watters, Jul 18 2006
Showing 1-2 of 2 results.