OFFSET
2,1
COMMENTS
Numbers can be used more than once.
LINKS
Giovanni Resta, Table of n, a(n) for n = 2..100
Ken Dutch and Christy Rickett, Conductors for sets of large integer squares, Notes on Number Theory and Discrete Mathematics Vol. 18 (2012), No. 1, 16-21.
Alessio Moscariello, On integers which are representable as sums of large squares, International Journal of Number Theory 11 (8) (2015), 2505-2511.
FORMULA
a(n) < n^4 + 6n^3 + 11n^2 + 6n by Sylvester's theorem. [Charles R Greathouse IV, Jul 14 2011]
a(n) = o(n^{2+e}) for all e > 0, according to Dutch and Rickett. [Jeffrey Shallit, Mar 17 2021]
a(n) = O(n^2), according to Moscariello. [Jeffrey Shallit, Mar 17 2021]
MATHEMATICA
a[n_] := Block[{k = 4, f}, While[ (n+k)^2 <= (f = FrobeniusNumber[ Range[ n, n+k]^2]), k++]; f]; a /@ Range[2, 45] (* Giovanni Resta, Jun 13 2016 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Remmert Borst, Jul 14 2011
STATUS
approved