The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157477 Number of values k < n for which k is a greedy sum of squares. 0
0, 1, 2, 2, 2, 3, 4, 4, 4, 4, 5, 6, 6, 6, 7, 8, 8, 9, 10, 10, 10, 11, 12, 12, 12, 12, 13, 14, 14, 14, 15, 16, 16, 16, 16, 17, 18, 19, 20, 20, 20, 21, 22, 22, 22, 22, 23, 24, 24, 24, 25, 26, 26, 26, 27, 28, 28, 28, 28, 29, 30, 30, 30, 31, 32, 33, 34, 34, 34, 35, 36, 36, 36, 36, 37 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
H. L Montgomery and U. M. A. Vorhauer, Greedy sums of distinct squares, Math. Comp. 73 (2004) 493-513, Table 1. [MR2034134].
MAPLE
greeds := proc(n) local arem, a, j ; arem := n ; a := [] ; while arem > 0 do j := floor(sqrt(arem)) ; a := [op(a), j] ; arem := arem-j^2 ; od: a ; end: isGreedS := proc(n) option remember; local L; L := greeds(n) ; RETURN( nops(L) = nops( convert(L, set)) ) ; end: a := proc(n) local resul, i ; resul := 0 ; for i from 0 to n-1 do if isGreedS(i) then resul := resul+1 ; fi; od: resul ; end: seq(a(n), n=0..80) ;
MATHEMATICA
greeds[n_] := Module[{arem = n, a = {}, j}, While[arem > 0, j = Floor[Sqrt[arem]]; AppendTo[a, j]; arem = arem - j^2]; a];
isGreedS[n_] := isGreedS[n] = Module[{L = greeds[n]}, Length[L] == Length[Union[L]]];
a[n_] := Module[{resul = 0, i}, For[i = 0, i <= n-1, i++, If[isGreedS[i], resul++]]; resul];
Table[a[n], {n, 0, 80}] (* Jean-François Alcover, Nov 29 2023, after R. J. Mathar *)
CROSSREFS
Sequence in context: A162351 A087816 A072000 * A248801 A006949 A359536
KEYWORD
easy,nonn
AUTHOR
R. J. Mathar, Mar 01 2009
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 20 10:51 EDT 2024. Contains 372712 sequences. (Running on oeis4.)