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 A072689 Difference between (least square >= n) and (largest square <= n). 2
 0, 3, 3, 0, 5, 5, 5, 5, 0, 7, 7, 7, 7, 7, 7, 0, 9, 9, 9, 9, 9, 9, 9, 9, 0, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 0, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 0, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 0, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = 0 iff n is a square. a(n) = 1+2*A000196(n) if n is not a square. - Robert Israel, Sep 22 2020 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A057427(n - A048760(n)) * (A000196(A048760(n))*2 + 1). a(n) = A048761(n) - A048760(n). MAPLE f:= proc(n) local t; t:= floor(sqrt(n));   if n = t^2 then 0 else 1 + 2*t fi end proc: map(f, [\$1..100]); # Robert Israel, Sep 22 2020 MATHEMATICA ds[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 0, 1+2Floor[s]]]; Array[ds, 80] (* Harvey P. Dale, Dec 05 2013 *) CROSSREFS Cf. A000196, A000290, A048760, A048761, A072690. Sequence in context: A128046 A102899 A353327 * A021972 A193451 A335809 Adjacent sequences:  A072686 A072687 A072688 * A072690 A072691 A072692 KEYWORD nonn AUTHOR Reinhard Zumkeller, Jul 02 2002 STATUS approved

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Last modified May 21 00:36 EDT 2022. Contains 353886 sequences. (Running on oeis4.)