A241835 Numbers k such that k^2 is s-greedy summable, where s is the sequence A000290 of squares.

5, 7, 9, 11, 13, 15, 18, 19, 21, 23, 25, 27, 30, 32, 33, 35, 37, 39, 41, 43, 46, 48, 49, 51, 53, 55, 57, 59, 61, 63, 66, 68, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 90, 92, 93, 95, 98, 99, 101, 103, 105, 107, 109, 111, 113, 115, 118, 120, 121, 123, 126, 128

Offset

2,1

Comments

Greedy residue sums are introduced at A241833.

Links

Clark Kimberling, Table of n, a(n) for n = 2..1000

Example

5^2 = 4^2 + 3^2; 7^2 = 6^2 + 3^2 + 3^2; 9^2 = 8^2 + 4^2 + 1^2.

Mathematica

z = 200;  s = Table[n^2, {n, 1, z}]; t = Table[{s[[n]], #, Total[#] == s[[n]]} &[   DeleteCases[-Differences[FoldList[If[#1 - #2 >= 0, #1 - #2, #1] &, s[[n]], Reverse[Select[s, # < s[[n]] &]]]], 0]], {n, z}]; r[n_] := s[[n]] - Total[t[[n]][[2]]]; tr =  Table[r[n], {n, 2, z}]  (* A241833 *)
c = Table[Length[t[[n]][[2]]], {n, 2, z}] (* A241834 *)
f = 1 + Flatten[Position[tr, 0]]  (* A241835 *)
f^2  (* A241836 *) (* Peter J. C. Moses, May 06 2014 *)

Crossrefs

Cf. A241832, A241835, A241836, A000290.

Sequence in context: A020735 A329391 A108144 * A279914 A123910 A024886

Adjacent sequences: A241832 A241833 A241834 * A241836 A241837 A241838

Keyword

nonn,easy

Author

Clark Kimberling, May 09 2014

Status

approved