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A124896 Number of squarefree numbers of the form n^2 + k^2, 1<=k<=n. 1
1, 1, 2, 1, 4, 2, 5, 4, 6, 4, 9, 3, 11, 6, 7, 7, 14, 5, 16, 8, 11, 8, 19, 7, 20, 11, 16, 12, 24, 8, 26, 15, 18, 15, 23, 11, 33, 16, 21, 15, 34, 10, 38, 19, 23, 20, 41, 15, 38, 19, 29, 22, 46, 15, 38, 22, 33, 26, 53, 15, 52, 26, 32, 30, 48, 18, 59, 30, 40, 22, 62, 21, 64, 32, 39, 34 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = Sum(A008966(A070216(n,k)):1<=k<=n) = Sum(ABS(A124895(n,k)):1<=k<=n).

0 < a(n) <= n-1.

LINKS

Table of n, a(n) for n=1..76.

MATHEMATICA

Count[#, _?SquareFreeQ]&/@Table[n^2+k^2, {n, 80}, {k, n}] (* Harvey P. Dale, Mar 30 2012 *)

CROSSREFS

Sequence in context: A086450 A270439 A106044 * A008742 A029136 A001479

Adjacent sequences:  A124893 A124894 A124895 * A124897 A124898 A124899

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 12 2006

STATUS

approved

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Last modified October 23 14:54 EDT 2019. Contains 328345 sequences. (Running on oeis4.)