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 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 Table of n, a(n) for n=0..74. 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 Adjacent sequences: A157474 A157475 A157476 * A157478 A157479 A157480 KEYWORD easy,nonn AUTHOR R. J. Mathar, Mar 01 2009 STATUS approved

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